The recent iPhone OS 3.1 release just a few weeks ago seems to have made things worse for a bunch of iPhone 3G/3GS users: Their battery drains really fast (warning: almost 1000 posts in that thread, might take you some time to read through all of them…).
The problem is apparently so huge that Apple decided to send a questionnaire with 11 questions on how the users are using their iPhone, to some of them.
Besides that, Apple also enabled “logging & reporting” at some users. Those logs will automatically be sent to Apple when the iPhone is synced with iTunes. I think Apple only enabled this feature at users who wanted it or approved it, so you don’t have to worry about your own usage pattern being sent to Apple – unless you agreed to do so, of course.
Personally I haven’t had any problems at all, including the battery, with iPhone OS 3.1 on my iPhone 3GS and 3G.
How about you?!