I have to say that I'm very happy with the 4S. While I've been using Apple products for a few years, this is my first iPhone.
For the past few years, I'd been using Android phones. While there are things about Android that I like compared to the iPhone, I'm much happier with the iPhone.
Battery life has been fine for me. I can get through a day with both Bluetooth and WiFi on, listening to podcasts a couple of hours a day, phone calls, some games, downloading new podcasts, web surfing, and have more than 50% battery life left when I get home. With my last Android phone, it would be down to 28% battery about halfway through the day - and that's with an extended battery, no downloading, and no gaming. (Actually, none of my Android phones got this kind of battery life.)
It took me a while to pull the trigger on the 4S. Ultimately, I just got tired of carrying two devices (a Touch and my Android) in order to have both a phone and a media device.
Currently, it's a stock, unlocked phone (jailbreaking isn't out of the question) running on T-Mobile.