Fitness Tracker

I like my Vivoactive 3, and would hope the VA4 would be same/better.

I feel like it does a decent job tracking heart rate with the wrist-based monitor: I've had very few blank periods when I've been wearing the watch, and the results seem plausible based on what I've been doing.

I have found that I need to use a chest belt with it when doing things that involve a lot of arm flexion. (Rowing is my main thing, on-water and machine: The chest belt is essential for that. Without it, I don't so much get drop-outs, but periods where my HR track doesn't make sense in terms of what it reports, so I know it was missing beats.) The integration with the chest belt is easy, in that it auto-detects/connects when I start an exercise activity on the watch.

I haven't much used the watch for strength training (because I'm a wicked human who doesn't much strength train ), but it does sorta count reps. I don't have enough experience to know how well it handles heart rate during strength training.

I'd point out that I'm in an advantageous position for a wrist-based HRM: Pale skin, not very hairy, etc.

I am also a vivoactive 3 user and love it. I had the vivoactive HR and then changed to the Galaxy Gear S3 (I think that is what its called) before they came out with the smaller version of it. I loved the Galaxy for phone related things but not so much for fitness, it was also way too big for my small wrist and actually changed the shape of my wrist. The VA3 is so much lighter although the watch face may be around the same size.

I have a treadmill with iFit and wear the iFit chest strap while on the treadmill and also log a workout on my VA3, my max HR and avg HR is always within 1-2 bpm between the two.

Some of those features aren't even in the new Fenix 6 line.

@AnnPT77 brings up a good point. Years ago Garmin earned a reputation for buggy software, and for not adequately testing new releases. Mostly within the cycling community (relevant because watches and bone computers are made by different teams) where they were and probably still are the 800 pound gorilla. It became a pretty regular practice for many cyclists to buy the second newest unit, or to wait a while for the firmware to settle.

Personally if I were in the market I'd be looking at the newest hardware (mostly for software features which is unfortunate) or wanting a discount on older stuff.