When choosing a fitness watch, it all comes down to your application. If you want a cool-looking device to show off on your wrist, the Apple Watch beautifully does the job. However, if you want great activity tracking the Polar Unite fitness watch is the better tool for the job.
As well as native sleep tracking and long battery life, Polar Unite cost a fraction of the price of an Apple Watch and, it doesn't require you to splurge out on an iPhone since the Apple Watch does not work with Android phones, whereas Polar Unite is compatible with iPhones!
The Polar Unite watch is designed in such a way that only the 6-o'clock strap (bottom section) is interchangeable. This means, if you wanted to mix and match different straps you could since you only have to replace the bottom section of the strap. The medium/large strap (long section) measures 13cm long.
The Polar Unite watch strap comes in two sizes (small and medium/large) and three materials (silicone, textile and leather). The small strap has a total length of 24cm long from one side of the strap to the other. The 12-o'clock strap (short section) measures 9cm long, while the 6-o'clock strap (long section) measures 10cm long.
The textile and leather Polar straps come with a traditional buckle fastening, which has the classic buckle and pin to adjust the fit of the watch on the wrist.
The Polar Unite silicone strap (pictured) has no buckle, featuring instead, a pin-and-tuck closure, which consists of a loophole and a pin on the short section of the strap that requires the long section of the strap to be slipped inwards.
Compared to the classic buckle fastener, the pin-and-tuck closure works well on the Polar Unite, although, it's not as forgiving on very small wrists as the classic buckle.
If your wrists are really small, the pin-and-tuck closure may not work well because you will have to bend more of the strap to tuck all of it inwards, causing the rubber pin to pop out of the hole.
The Polar Unite watch has been designed to accommodate standard 20mm quick release spring bars; hence you can use any third-party watch straps you want. Being made of silicone, the Polar Unite strap is more comfortable than a resin plastic and will not split when twisted.
Silicone feels like natural rubber and performs like it too under heat and cold temperatures. Silicone also has the same odor-free and hypoallergenic properties as natural rubber, unlike TPE rubber, which is also used to make watch straps.
The Polar Unite silicone strap has a smooth finish on the underside and brushed-like finish on the front of the strap.
The underside of the strap is grooved with shallow indentations the entire length of the strap, which allow airflow and thus, minimizing sweat under the watch while preventing the watch from becoming too slippery on the wrist.
The case back on the Polar Unite watch is made of glass fiber reinforced polymer and etched information that includes the serial number, ID and WR30 water resistance, which means Polar Unite is suitable for swimming, not diving.
The case back also integrates the same Polar Precision Prime optical heart rate sensor found on the Polar Grit X watch, which combines multiple sensors to monitor heart rate and software algorithms to detect skin contact.
The led sensors are arranged in a cross-like pattern and housed inside a circular glass panel, which sits flush, making the Polar Unite case back smooth and more comfortable to wear than the Polar Ignite fitness watch and Polar Grit X, which have a bump heart rate sensor.
Speaking of Polar Ignite, the new Polar Unite shares many similarities including the circular body shell, single physical stainless steel button and "wrist raise activation" where the display turns off automatically within a few seconds and has to be woken by a firm shake of the wrist.
If you prefer to have the display "always-on" though, you do have the option to enable this from the watch settings. You can also disable heart rate tracking or enable it for night-time use only.
Polar Unite does not support NFC (for contactless payment) nor onboard music storage capability like the Polar M600 does, which has 4GB of internal storage. There is no GPS functionality built-in either but, you can use your phone's internal GPS, just like with the Polar A370 fitness band.
Being able to leverage off your phone's GPS means Polar Unite is capable of better battery life, up to 2 days (with heart rate turned on too) versus 16 hours runtime with the Polar Ignite GPS watch. Without GPS use, Polar Unite is capable of up to 4 days of battery life while heart rate tracking is enable too.
Depending on your preference, GPS may or may not be a deal breaker, although there are several advantages to having internal GPS, including better accuracy, convenience and safety.
With the Ignite GPS watch, you can quickly glance at it to see your current pace without having to pull out your phone mid-race or when running in the rain.
If built-in GPS is no biggie, Polar Unite is a good offering because it's cheaper than Polar Ignite and capable of providing daily training schedules based on your own performance, recovery, breathing rate and heart rate. Polar Unite also tracks sleep, it can guide you with breathing exercises, help you create workouts and give you feedback after each workout.

In terms of accuracy, Polar Unite is accurate as you can get with a wrist-based heart sensor but not as quick to respond to sudden changes as the Polar chest strap as there is a bit of a delay when registering a sudden peak in pace. That said, Polar Unite does support Bluetooth Smart; hence you can pair it with other devices.
There is no support for power meters, running footpod sensors and cycling sensors though; hence you won't be able to connect Polar Unite to the Polar V650 GPS cycling computer.
The Polar Unite internal 174 mAh lithium-polymer battery has 500 times life cycle and, it recharges via a new proprietary charging solution that consists of a plastic retainer that clips on to the case back of the Unite watch. To extend the life cycle of the battery is a good idea not letting the battery drain and to recharge the battery when it's down to 50%.
The plastic retainer has gold plated contacts and a low profile USB-A connector at one end to insert into a USB port of a computer for charging and syncing data. You can recharge Polar Unite via any 5V source, which means you can use a power bank to recharge the watch. It is strongly advised against using higher voltage (i.e. 9V).
Initial set up of Polar Unite can be done via the Polar mobile app or, via the FlowSync desktop software, which allows syncing data via a Windows computer or Mac computer.
The new 3.0 version of FlowSync doesn't support Windows XP or OS X v10.8 (it does support Windows 7) so, if you are running Windows XP or OS X v10.8, you will need to use the older version of FlowSync.
As a daily smartwatch, Polar Unite works great since it tells time and date and, you can set wake-up alarms and inactivity alerts. There is no speaker built-in so, Polar Unite uses vibration (similar to a smartphone) for the alarms and alerts. You can disable vibration too.
As a fitness watch, Polar Unite offers a lot of sport features with a fairly comprehensive breakdown and tailor-made workout suggestions similar to the Vantage M fitness watch, although not as in-depth since Polar Unite does not integrate Training Load Pro or Recovery Pro.
Polar Unite uses a touch sensitive color IPS TFT display with 240 x 204 resolution (and 43.4mm diameter) that integrates an ambient light sensor. Menu navigation is done by swiping from side to side and across the screen from top to bottom, which brings up a shortcut menu to quickly access key settings such as brightness, airplane mode, alarm and lock screen.
The display is protected by Asahi glass (same as Apple Watch Series 4) so, the screen feels durable, which is nice, although swiping feels a tad laggy. This could be due to the thickness of the glass or perhaps, the test watch, being a Beta sample.
There is no ability to turn off the Polar Unite watch but the watch can be restarted by going to settings >general settings > about your watch and then, scrolling down to the bottom of the screen where you will see "restart watch".
As far as accessories, Polar Unite ships with just the charger clip and wrist strap already attached to the watch. You can buy the Polar Unite fitness watch on amazon. Check out the review of the new Polar Vantage M2 sports watch and Ignite 2 watch.

They call it a marketer's dream when a product is absolutely unbeatable because it is cheaper and comparable to the competition!
The Letsfit ID131Color HR fitness tracker has all of the attributes marketers dream, including features seen on more expensive fitness trackers like heart rate, step count and calorie counter, and only costing a third of the price!
The construction of the Letsfit ID131Color consists of a polycarbonate body and thermoplastic polyurethane silicone wrist straps.
The Letsfit fitness watch is extremely lightweight on the wrist, weighing just 29 grams and totaling 28cm in length. The body of the watch itself measures 6cm long and 1.5cm thick.
The removable silicone wrist straps fit snugly to the body of the watch, concealing the male USB-A connector and giving the watch an IP68 resistance.
The USB-A connector allows you to insert the Letsfit ID131Color HR into the USB port of a laptop or desktop computer so you can charge it.
It's nice that the Letsfit fitness watch uses a universal connection as opposed to a proprietary connection like some fitness watches.
Universal connection is nice, but having to remove the wrist bands to access the USB connection makes the Letsfit watch not as convenient as fitness watches with a port connection that you plug a USB cable into.
The 90mAh lithium polymer rechargeable battery charges via 5V 0.5A so full charge takes approximately 2 hours. There is no way to turn off the Letsfit fitness watch but standby battery life is very long (7+ days).
When enabling phone notifications and heart monitoring, the battery life does decrease quite a bit to about 3-4 days battery life, depending on how long you use these features for.
Letsfit ID131Color HR fitness tracker comes with two companion apps, VeryFitPro and VeryFitPlus. The latter doesn't work as good because of functionality issues where the VeryFitPlus app randomly changes the language on the phone, and the watch data taking too long to update on the app.
No functionality issues are found with the VeryFitPro mobile app, which works very well and has a more user friendly design layout where the user can see at a glance their activity data, sleep data and heart rate data.
Considering the price of the Letsfit ID131Color HR fitness watch, the VeryFitPro mobile app provides a lot of data to the user, as well as the ability to set vibrating alerts so the user can be alerted when they are sitting for too long or when they receive an incoming call. There is also a "camera mode" that lets you shoot pictures on your phone from the watch.
From the VeryFitPro mobile app, you can also adjust the watch's display brightness, heart rate zones, step length, and even reboot the device. Speaking of brightness, the max brightness of the watch isn't particular bright in daylight but bright enough that you can still see the display.
Unlike other fitness watches, which have a larger and brighter display and can be used standalone without an app, small fitness watches such as the Letsfit ID131Color HR are mainly tracking devices that depend on their companion app because of their small display to be able to make the most of their features. The screen size of the Letsfit ID131Color HR is 0.96 inch.
If your smartphone has a bright display, the brightness on the Letsfit ID131Color HR fitness watch won't be an issue since you'll be able to access and see the data clearly on your smartphone.  The Letsfit fitness tracker uses TFT LCD color display.
The data provided by the Letsfit watch and the VeryFitPro mobile app is pretty comprehensive and updates on the app almost instantly.
The VeryFitPro app also lets you change the language of the watch and lets you see at a glance how far you are from your daily target. You can even share the data to social media.
The mobile app connects to a phone or tablet via bluetooth 4.0 and you can only have the watch connected to one device at a time.
There are no physical buttons on the Letsfit ID131Color HR. User control consists of a multi-functional touch sensitive button located on the bottom of the screen that allows you to navigate and access the menus by tapping and holding.
There are a total of seven menus, including the main screen that shows the time and date. There is also a menu screen for the step counter, heart rate monitoring activation and activity screens (walk, run and bike).
There is also an alarm menu screen which only appears after enabling the "Alarm Alert" from the app.
The heart rate sensor built-in to the Letsfit ID131Color HR fitness tracker works very well, being able to track your heart rate quick and reliably.
Heart rate monitoring is carried out via two green leds and one light-sensitive photodiode that do a good job at measuring the blood flow through your skin.