Bests & Worsts Reviews from Amazon

I have been a dedicated Polar user for years as a competitive athlete. I still use my Polar M400 with great success; however, I was really hoping to ditch the strap after 15+ years. Below are some pros and cons that I found: Pros 1. I do like the button layout since this is the standard (or has been) for Polar so if you’ve been using Polar, it’ll be much easier to adapt. 2. I’m not a fan of touch screen watches. I train to train, not to play around with watch faces. I completely get the fitness enthusiast that wants a fitness/smart watch they can wear all the time. I probably like this watch’s button navigation process because it’s what I’m used to in prior HR watches. 3. It has a clean look. Much better looking than the older Polar watches or those space-age looking watches. It might be a little big on someone with thin wrists. Cons 1. HR measurement is not accurate. I did multiple comparison tests with my Polar M400 strap watch, with several different types of training modes, and readings were erratic. HR readings were closer to what the strap gave when there was less distal movement or wrist movement. At rest it was close (most of the time) but once I started to increase my movement and exercise intensity, the readings were inconsistent. For performance based training, this would NOT be a good choice. 2. Kcalorie expenditure was off by at least 20% (lower than strap monitor). This makes sense if the HR readings were off. For those trying to gain or lose weight, it would NOT be a good choice either. 3. In my opinion, the size of the watch is fine for a man’s wrist, but may be large for a woman’s. Of course, this is completely subjective since I do know some women that now like larger watches. Keep in mind that most comparable watches from other competitors are similar. 4. The sync and customization options are limited, even when you use the computer app, which has slightly more options than the watch and phone app set-up. I would love to be able to lock the screen so I don’t inadvertently hit a button that might pause the session, or whatever. 5. I’d love to have a brighter screen and a way to keep the light on. It does turn-on with a flip of the wrist, but it’s not always reliable and I don’t always need to turn my wrist to want that. 6. The charger is horrible. Rather than a straight forward wall-to-watch plug, its some fancy magnetic connector. The USB cord from the wall extends to a magnetic attachment which easily detaches from the watch if its not laying on the watch face. Hard to explain but you'll have to look at some of the online videos to get it. Just a note: I did the same comparison testing with the Garmin VivoActive 3 (versus Polar M400), and it was just as bad. In fact, for fun, I got my hands on a FitBit Alta HR and it actually had better readings than the Garmin or Polar; but still not accurate enough for me. Either way, I don’t think they’ve perfected this wrist based technology yet. I questioned it's accuracy when it first came out but after reading an article saying it was very accurate compared to the "old strap" monitors, I thought I'd give it a try. I was really hoping this would be it; I REALLY want to ditch the chest strap...but not willing to sacrifice accuracy. Perhaps the watches at a much higher price-point work better, but I’d guess it would be the same. My next step is to test the arm strap. Good luck.