I KNOW THIS SITUATION *****, BUT CHILL FOR A WEEK OR TWO ....
This is almost certainly a software related issue. I had my AT&T 64 GB White iPhone replaced by my local Apple store and the new one has all the same problems as the old one. At the same time; I know of several people, including close relatives, who aren't having a single issue with their battery life. The odds of me getting two of the small percentage of phones exhibiting this problem (if it is hardware based) are astonmically small. Remember, just because you see tons of posts here about battery issues; compared to the millions of 4s devices already sold and activated; the number of users on this forum is miniscule! )
It really ***** to pay for what is supposed to be the greatest device ever; only to be disappointed by something like this; however, APPLE IS ACTIVELY TRYING TO DIAGNOSE THE CAUSE AND PROVIDE A FIX! I know, because I am one of many from this forum who have been contacted by Apple Tech Support and asked to participate in a diagnostic program. The tech emailed me a minor OS patch; which creates an extremely detailed log file of my phone's activity. Every time I sync to iTunes it transfers the log file to my Mac. I then attach the logs to an email back to Apple Tech Support. The First sync; approximately 9 hours after installing the patch created a log that was over 8 MB in size. Considering that this is almost certainly a text only file - that's a huge amount of data.
Clearly; Apple is trying to compare log files from multiple effected users in an attempt to find commonalities. Once this is done, they can experiment with disabling various combinations of system settings and/or software. I would never expect this scenario to be performed with any expectation by Apple to tell people to simply not use a feature. (Unlike Antennagate; this is almost certainly software related -thus fixable) Such a hypothetical series of tests with features of applications disabled would be a logical means for norrowing down the source of this problem. Once they know where to look, they can dig deeper into the specific code to find and fix the problem. As someone who has developed and debugged software, I know that this is not a quick and easy process; especially when you throw in hundreds of thousands of independant applications which could be interacting with the core operating system.
I wouldn't reasonably expect Apple to fully diagnose and provide a fix for this problem for at least a couple of weeks. (unless they get really lucky with early diagnostic log files.)
THE MAIN POINT THAT I AM TRYING TO GET TO is that while this situation is a real pain in the a$$, frustrating, irritating, annoying (and throw in any other adjectives you wish to provide) there is really NOTHING that your local Genius Bar or Apple Telephone Tech Support can do to fix this problem. Until the actual iPhone development techs find and fix the bug(s) involved; customer level tech support will not be able to provide any reliable advice. I mention this; because, I am seeing a large number of posts from people who imply that they are becoming somewhat confrontational with Apple support staff. (Not all; but some) For those who are aggrevated by their 4S Battery problems and get upset when tech support can't provide an immediate solution or refuse to just give you another phone (I was one of the earlier users to discover the problem and work with my local Genius Bar to find a fix. Knowing that a replacement phone did nothing to fix the problem; I know it is a waste of time and resources to ask for another replacement. It won't do me any good and it takes a perfectly good piece of HARDWARE out of the supply chain.) Consider how you would feel if you were in the shoes of Apple Support; unable to provide an answer, due to the fact that the problem is too new for them to know much of anything to help you out?
I plan to continue sending logs to my Tech Support contact and try to comply with any requests they may have to turn certain features on / off; temporarily remove potentially offending programs, or comply with any other reasonable suggestions they may have; which may lead to a fix.
What I won't do is try any more fresh OS reinstalls or installations as a new Phone (vs. an upgrade) as this would simply be time consuming and frustrating. I have already tried the first approach and have read multiple posts from people who have done the second; without any detectable improvements in battery life. (Einstein once said that Insanity is doing the same thing over and over again, and expecting different results.) If nothing else; wasting my time on something that has already failed multiple times, would drive me insane. Unless Apple Tech suggests that i perform such a reinstall IN COMBINATION with something else that has not been tried; I'll cope with keeping my phone close to a charger for a week or two.
If we get close to Thanksgiving (For those in the USA) without any sign of progress; that's when I'll start to openly gripe. Until then, I'll keep in mind that $hit happens; and remember that there are talented programmers / debuggers at Apple who are working hard to find a fix. Give the rest of Apple employess a breif break and let them devote their time to helping customers with issues for which they actually do have answers to.