I came from Garmin and the Apple Watch is great. The workout tracking is excellent and unless you’re a serious athlete or training for a triathlon, it gives you more than enough data with the built in workout app, and you can also use third party apps like Strava or WorkOutDoors (or use HealthFit to sync)
I never really used the Body Battery or the stress monitoring, both of which I found somewhat gimmicky and I was sceptical of the science behind them (especially the body battery).
And of course the non-fitness smart watch features are no comparison, Apple Watch by a mile
Battery life took some getting used to but you can get into a routine to charge it every day and it’s fine. In some ways better than having to keep track of the battery to decide when to charge it
tbh if you have an iPhone then I wouldn’t bother with anything other than an Apple Watch. It’s a good watch, but the main issue is that other watches don’t play well with iOS. I had a Garmin paired with an iPhone m and the notifications were a bit of a mess and they can’t be customized
More choices if you have Android (though obviously Apple Watch doesn’t work)