To be fair, my Series 0 runs fine. Never had any bother with slowness. The battery is getting on a bit but the new watches still don't have very good battery life so it's hardly worth paying £400 for a new watch with only slightly better battery life.
Do you use it for exercise? When I click Workout on my series 0 it often takes a good 10 seconds before the watch is responsive and I can scroll to select/begin workout. When ending a workout, clicking the stop action is slow, 5 second or so pause before I can scroll to the final screen and click done.
Since I workout on average 5 times per week that's the most annoying constant thing for me.
Some other annoyances:
When I get a text and scroll to click to Dismiss. The ui is sometimes initially laggy and unresponsive. When this first started happening probably a year ago I'd end up sending a wrong canned message by mistake instead of hitting dismiss. I anticipate the slowness now so it's just something I learned to deal with, although this doesn't happen every time. Maybe a couple times per day at most.
Sometimes when you press the digital crown to get to the list of apps it's unresponsive so you press the crown for a second time. Eventually it'll go into the list of apps then back to the main screen. Technically you pressed the button twice so it's as it should be, but the reason for the 2nd press was after waiting it seemed as if the first didn't register.
The workout app issue. Those that I know with a series 0 have the same problem. My wife has a series 3 and doesn't experience any of my problems.
I've restored the watch, closed all apps, etc.. Although as I know several people that experience many of the same issues I didn't expect any of the things I tried to resolve anything.
Battery life has never been a problem for me. I typically charge it after I workout and I'm getting ready. Beyond that I seldom need to recharge other than at night.
