I got the 4s during the pre-order (Verizon, 64G) and initially saw the issues with the battery, read all the posts here and elsewhere. I then turned off Push (check every 15 instead), Diagnostics (the Send to Apple setting), Auto Time Zone, and any iTunes sync that wasn't via the PC. Tweaked some notification services but they are mostly on. I play with Siri occasionally but don't use the obvious location-based reminders as that clearly will use GPS a lot. iCloud mail and reminder sync was/is still on although I may have turned it off for a day or two but turned it back on. Exchange and Gmail are still on, check every 15. My phone comes off the charger at around 6AM and generally with normal use throughout the day including plenty of email checking, some browsing, maybe 60 minutes of calls, some music, occasional youtube video, and plenty of texts it hits the charger when I go to sleep around midnight with somewhere between 50-70% of it's battery depending on the day. That's better than my Moto Droid2 with the extended battery which I thought was the best of *any* smartphone I've ever owned except maybe my OLD blackberry that didn't do much besides email and calls with a little lame browsing and no color. So if that's "bad" to some original iPhone 4 users who kept theirs off the charger for 3 days straight...you're spoiled. This is still by far the best battery life I've ever had. If I leave the phone sitting on my desk for a couple of hours, MAYBE it drains 1-2% but more likely it's at most 1% or not at all. I do use WiFi at work and home so it's always on.
Along came 5.0.1 and like a complete idiot I went to fix what wasn't broken without reading here first. OTA 5.0.1 update ran while I was sitting in a meeting and finished, restarted and had around 93% battery when it was restarted as part of the update. After my meeting I walked across the street to get lunch and only glanced at emails but no talking, surfing, texting or anything and I noticed the phone got hotter and was down to 84% before I got back. Not good, so I quickly read what was already spreading like wildfire and aside from all the tweaks I did above the only suggestion I saw that made remote sense was to perform a full reset (hold home and power till it gives the Apple logo, not just power off) and then I charged it to 100% at my desk. Did not change ANY other settings but I did verify they were all the way I had left them. I personally think the whole drain the phone to zero a few times might help but only provides incremental improvement, not full recovery from the rapid drain except possibly because in effect it's a full reset when it turns itself off.
Anyway the effect was immediate, pretty much no different than the original 5.0. Not better but no longer dropping like a stone. I charge my phone every night because I use it as an alarm clock as well but I think the root of the issue here is ONE setting or rogue app could easily send the device into a CPU frenzy and until you find that one thing you'll be frustrated. Doesn't even have to be the same setting as the previous drain-inducing problem. I read suggestions that included simply turning the email sync (or calendar or whatever it was) OFF and then back ON because as silly as that sounds in the land of software that's an easy one to be one possible cause of a problem.
Probably not hardware although I'm sure there are devices out there with random issues but for the general case, I think it's software. Sadly sending diagnostics is probably something we all turn off because it was one of the obvious choices and might actually be one thing that gives Apple more information with which to figure out what's chewing up cycles.
Sorry for the length but hope it helps...
