C39G here (64gb black).
Great battery life, much better than the 3GS it replaced. I have not disabled anything. Three "push" email accounts (icloud, gmail setup as exchange, yahoo), several pop3 accounts set to manual (which I usually check every hour or so). Location services on, bluetooth on, wifi on, etc. I typically get to the end of the day with >50% left, whereas with the 3GS I was frequently down to 20%. When not used (other than perhaps a notification or two), it seems to burn about 1% every 2 hours.
Just my opinion, worth every penny you paid: I really have to believe the battery problems some are having is environmental. By that I mean it is something about their particular 3G signal strength, or particular wifi router brand/model, or particular application mix, or some setting (especially if restored from a previous OS).
No doubt there are some "bad batteries", but when it follows you to two entirely different 4S units (your original, and the replacement) then it seems more likely the problem is not the hardware, but something interacting with the hardware.
