I bought this watch primarily for the always on feature, having had a smartwatch before where you have to lift or press a button to tell the time. That works, but you should know that the special faces are only on for a short time, then revert to a much simpler digital or clock face version. I assume this is to save on the battery.
The altitude and compass don't work very well, and the sleep monitoring includes as sleep all the time you are in bed, and not allow for when it's hard to drop off.