There is a long list of negatives:
- Battery life is miserable compared to a classic watch
- Screen activation is unreliable. Imagine a classic watch not visible when you look at it.
- Bad UX. Somehow the brightness settings I apply randomly get reset/reverted. This is probably hit or miss depending on brand, I expect Apple's devices have this nailed.
- Outdoor performance. This is the worst one. The screen is just not readable under bright sunlight. I find myself making a little tent out of whatever I have on and furiously shaking my wrist to activate the screen just so I can tell the time. This is what's going to make me ultimately switch back to a classic watch unless I can find one with e-ink. I'm not sure how Apple's devices fare here beyond friends saying 'it works fine.'