Obviously these need to have some kind of accuracy. Ideally, they would also come without vendor lock-in, but, of course, that's more and more rare.
Do you use any health wearables or recommend any?
Overall I like it, it looks like a normal watch with a small circular display which also gives me notifications. You can customize which app notifications show up on the watch. They have an API you can sign up for to pull your data but I haven't tried that yet.