The new 4S was supposed to have bested the battery life of the iPhone 4. While Apple touted an extra hour of talk time there was some head scratching over their admission of less standby time.
Now there are now reports that Apple is investigating poor battery life from users that claim their phones to poop out after just a couple of hours, even with apps closed and little 3G usage.
My personal experience with my 4S is that the battery will drain faster, but I think a lot of that is if you have geo-location using reminders and because I’ve been using Siri so much. I do also know that there are apps that are not “sleeping” properly and continue to use a lot of battery life, the Facebook app in particular seems to be very guilty of this. I manually close the Facebook app everytime I am done using this.