Samsung's Galaxy Watch 6 is the best Android watch for most people. Both the Galaxy Watch 6 and 6 Classic have incredibly bright screens that hit a maximum 2,000 nits, so seeing your watch in all lighting conditions is easy.
All the flagship features you would expect are included: an ECG, blood oxygen, body composition and temperature sensors. Note that you do need a Galaxy phone to use the ECG, but all the other features work seamlessly with other Android phones.
But overall, these watches are similar to the Galaxy Watch 5, only offering incremental updates to battery life and screen size. You'll still need to charge the watch every day, especially if you want to track sleep.
Last year's Galaxy Watch 5 Pro remains in the lineup if you need the best battery life of any Galaxy Watch, lasting up to three days on a charge.