I have a Withings ScanWatch. Was pretty much what I wanted in a smart watch: looks like an analog watch but has discreet notifications plus the fitness features. I got it because I wanted to track EKG, which it is very good at (I was able to provide the readings to my cardiologist who accepted them). However, the HR monitor (using PPG) is now malfunctioning and it's out of warranty and there's no repair options, so it's just sitting on my desk and I'm back to my "classic" watch.

Also, it wasn't fully waterproof (5 ATM is not enough) and I didn't like having to take it off to go swimming etc. My classic watch is 20 ATM.