I'm going to have to test a regular watch face tomorrow but I can confirm that the watch loses about 5% every half hour and lasts close to nine hours before it goes into power save mode. I refuse to allow that and it ends up dying around eleven hours. I think tomorrow I'll try a regular watchface and see if it's the OS or Facer.
In fact last night I took it off the charger for maybe about an hour and a half to two hours tops. I just left it on the arm of my chair as I did other things around the house and I never bothered to put it on. When I picked it up before bed to put it back onto the charger it was at 87%.
I'm running version 188.8.131.52 on a Gear S3 Frontier LTE version.