I am having noticeable problems with battery life, actually. I had my phone fully charged before I went to the Twins game last night. I did use it some to show my parents a few cool things, and to take and post a couple pics on Facebook. I also called Jeanna once.
By the time I woke up this morning it was dead. I had it on the car charger for 30 min on my way to work, and that only got it up to about 15% power. It is now dead again after only using it a couple times this morning.
I would say it probably only lasts 4 hrs if you are using it constantly... that seems about right. Otherwise, it will be dead after a day of normal use.
I don't know if this is in line with other smart phones like the iPhone or the NexusOne. Maybe Eric can comment on his iPhone.
The size was an issue for me at first, but I am getting used to it. I still think I would like a slightly smaller phone a bit better, like the iPhone or Incridible. If they have a significantly longer battery life, that would be a definite plus for those phones. The only real advantage of this phone is the large screen (if that is important for you) and the 8MP camera, which does take nice pics. It does also have a pretty cool multitasking and notification feature.
I dunno... the iPhone4 may be better, but who knows since it isnt out yet.