I have never complained about the battery drain, but it just hit me with 25.00 (or one of the latest alphas/betas before).
Nothing changed with the configuration, watchfaces, settings and such, but the watch keeps losing about 10% a day even if I am not wearing it.
The reactions for key presses is massively delayed (like a 4-5 seconds wait time before anything changes - i.e. the menu with a list of activities appears after I press the button) - looks like some process keeps running in the background using the watch's resources, draining the battery and interfering with the responsiveness of the whole user interface.