I'm extremely happy with the battery on the One. After a full nights charge and unplugged at 6:00am I have about 20% battery left when plugged back in at 11:00pm. I would say I'm your typical average/moderately heavy user. Typical days consists of 40-50 photos, 5+ Zoe's, 2 hours on the web and FB, 20 text, handfull of emails, maybe an hour of calls, and I use the IR blaster for at least an hour per day.
The majority of the time I'm connected through a strong wifi signal so maybe this helps my particular case?
I also have power saver mode enabled but I leave the display brightness unchecked.