first of, I just started swimming again, so I only used them twice. Setup was pretty easy ( I am pretty tech savvy) so no issues there. After setup, A update to the firmware was required, and it took a bit for the phone to connect back to the goggles. Unfortunately, all the settings that I had changed were set to default again after the update. Swam twice and each time, the googles needed to be cycled to be recognized so it could sync to the phone. That was the bad part. The best part: it does really work well. It keeps exact track of the rest you take, the amount of yards you swim, without doing anything.
As said, you get past the small issues, and it is a go. They also do not fog up (sofar), but eventually they will (they all do). They do not leak and are comfortable to wear. It is nice to have the extra nose wings, I did not need them though. Any improvements: Better sync, or connect automatically when near the phone. Better case for protection.
I would recemmend these to anyone (and I did at my practice). They are much cheaper than other smart goggles, so go for it