As a person who posted here before I got my 4s, and now posting as someone who's had the phone all week - the battery complaints have been a complete non-issue!
Seriously, I had a BlackBerry 9700 overloaded with apps and I'm pretty sure the battery life of this new phone is BETTER than my venerable RIM device. Could that battery life degrade over time as the battery ages and I put more and more on the device? Sure.
But if you take the proper care to turn off garbage notifications, shut off radios you aren't using, turn off Ping, etc., I think the battery life is pretty good. And just as important, it charges quickly, especially with the iPad 10W adapter.
If you're on the fence about getting a 4s, don't let the battery stories be a deciding factor. Particularly when the alternatives are something like the Motorola Razr, which has battery problems of its own (yes, due to 4G).