I could not decide which new Withings ScanWatch to get (Light or 2). I've been using their Body Comp scale for about 6 months. I'm really impressed with it (especially compared to my previous Smart scale (F.....) that just would not stay paired. But I loved that their watches had 6-7 days of battery life. That being said, I have the latest fruit watch, and I have to charge it more than once a day, it's get about 20hrs on a charge. And I've never liked how it looked. When I first saw the Withings original ScanWatch I wanted it. But it was missing the heart rate, and O2 monitoring, and its sleep functionality seemed lacking. These 2 new watches (except for O2) both seemed to fit my requirements. Neither have GPS built in but both can pair with your smartphone to acquire GPS info, which helps reduce battery usage. That and the small round OLED on each watch uses much less power than a full face's display. And call me old (school), but I really want my watch to look like jewelry rather than technology strapped to my arm.
Upon unboxing the two the Light has a perfectly flat crystal, and the "2" has a slightly raised convex crystal (made of Gorilla glass or Sapphire crystal, stronger and more scratch resistant than the Light). The "2" is 38mm wide and the Light is 37mm wide (you can't tell the difference). They ship with slightly different chargers, the "2" is expandable and could hold a wider watch, the Light is a fixed width, both can be used on either watch. They are both made of a shiny stainless steel, the "2" having a rounded case, the Light being more squared off. The "2" weighs 54g (1.9oz), the Light weighs 47g (1.7oz). For comparison my fruit watch weighs 69g (2.4oz) and has to be charged every 20h, and supports a 'special' magnetic wireless charger, the ScanWatch has a cradle it can be put into to charge. The ScanWatches both come with an attractive, comfortable silicone band. One issue with both ScanWatches that disappoints, is can you see the the time at night without touching the watch (you put it on your bedside table and turn out the lights), well the "2" has some bioluminescence, if the watch face has had sufficient light hitting it, before you turn out the lights, the watch arms glow for a few hours. The Light lacks this feature, really can't explain why besides their arms are more narrow. If you push the crown the date and time does show up in the OLED display for about 12s. One clever feature that both watches share is, when you push the crown the arms of the watch spread to 10 & 2 so the OLED face is clear of the arms.
Are the functions accurate.... I compared the BPM data from the two watches to my fruit watch. The 3 were typically within 2 BPM of each other. The step counters of the two were within 100, after 3000 steps, with the fruit watch in between the two. After exercise, the Light recovered more slowly than the 2 or the fruit. but after 3-5m all were together again. The SpO2 level of the "2" was +/-2 of the reading on the fruit, the averages were essentially identical. The ECG data was also nearly identical, but the graphic presentation (see last image) from the "2" was better to "read" than the fruit's presentation. The body temp data I found very interesting, you again have to use to visualize, but the granularity of the "2" is much better than the fruit, this info is not available from the Light. This was most interesting when exercising, you can easily see how your body temp rises, to a point and then plateaus. And then slowly drops after you stop (as does your HR, but it recovers more quickly). Withings provides you ECG data to a health group: Heartbeat Health (with your permission) were they to see an abnormality (afib) they would apparently contact you. Kind of a cool feature I don't plan to utilize. Both watches offer min/max heart rate notifications, that you can set the thresholds for. The fruit offers only high notifications. Both watches also monitor your respiration rates; Breaths/min it does this at random intervals, but during your sleep it can indicate good/poor/restless sleep. Now my previous f....t smart watch could not monitor my sleep (which is why I stopped using it, it worked fine for my wife). My fruit watch consistently measures my sleep time about 2hrs less than actual, and rarely captures REM sleep,but does see deep sleep. The Withings watches gave me more credit for more Deep or REM sleep, but it lumps the two together, whereas the fruit watch identifies Deep and REM separately (not sure how either is accurately determined). The average Heart Rate is available from both and it is presented in the Withings app much better than in the fruits Health app, which shows the heart rate and an hourly range, where the Withings app shows continuous data.
The Withings watches both support notifications tied to your phone. You get caller Id info (name and number) and you can select what other applications you want to get notifications from, you can select other apps like Calendar, Facebook, Gmail, and any other app that you might have installed on your phone. I've not found a way to decline incoming calls, or to force a message to be taken from the watch. Something I can do from my fruit watch. But other than that you can get a full range of notifications displayed on both watches. This is the feature I like/use the most on my smart watch. I rarely if ever pick up a call on my watch, I just want to know who's called or messaged, then I use the phone's bigger screen.
Overall I'm very impressed with both watches. The feature I miss the most is the ability to see the time at night in a dark room without touching the watch (maybe add a shake feature that turns the OLED on for 10s). What surprised me the most was the comfort of both watches, the silicon bands have small ridges on the back, this prevents the watch from sliding around on the arm, staying where you put it is huge. With the stock band I spend 1/3 of the day realigning the fruit watch on my arm. I'm sure the lighter weight of the Withings watches helps. The Withings bands are easily detachable, so if you want different colors for different occasions it is easily done, in a few seconds. So it becomes a question of is the ECG, Body temp and SpO2 levels of a great value to you. I'm guessing if you're not an athlete, someone who's doctor has interest in monitoring this data (which can easily be shared with health professionals from within the app). It's a cost issue. I think the flat glass on the Light is more attractive/easier to read, but the scratch resistance of the Gorilla glass on the "2" is a nice feature if you're concerned with scratches (I've not tested the scratch resistance of the two, and don't plan to). I love the appearance of the watches, and would happily trade my fruit watch for either. One other interesting note, when you install more than one watch the Withings app tells you that "you successfully installed an additional tracker. You can switch devices anytime you want, we take care of the rest". It's good to know it also includes Nokia watches, Apple Watch data via the Health App and iPhone sensor data via the Health App. Very well conceived, I can only imagine that their excellent app will continue to improve.