Well hello fellow iPhone 4S users, I'm not usually a 'good person' by posting threads or replies but guess this shall help many who have been annoyed by the 'battery gate' of the new handset. Sorry for long essay post... I have been using Apple products for over 10yrs now and used all iPhone models and more importantly experienced same excessive battery drain since getting my iPhone 4S, my iPhone 4 with iOS 5 didn't experience as bad as the 4S so here's what I found: I restore the 4S from iTunes and noticed a battery drain around 15% per 7hrs standby with all App in 'background' closed by double click home buttom. I had notification on, localization on, Siri on, iCloud off, WiFi sync on and mail check hourly. Basically all the goodies from Apple latest offer on, I agree with people, if switch off them what is the point having the new handset?! Having been annoyed by the poor battery performance, like many of you then I googled this and read a lot feedbacks and after trial and error I believe I finally catch the culprit. I did a full setting only reset, i.e. Keep all contents. Last night after full charge to 100% I managed to leave it untouched for 10hrs, with notification on, localization on, system feedback on, Siri on, WiFi on, mail fetch hourly. Usage indicated 10hr standby 15mins use(guess mail?) and 96% remaining!! Now what's off: WiFi sync (didn't test it but believe even leave it on shouldn't affect battery that much), iCloud off (read someone had sync issue with it which drains excessive battery), Ping off in restriction, Cellar data OFF. Look at the last item which I set it as off - cellar network data. From previous experience I knew in my house I got poor 3G connection (live in a village outside London), with my blackberry and all iPhones. There you go, I think, the poor, or say not very stable 3G connection causing the handset to constantly trying to maintain connectivity result in excessive battery drain. I did in the past switch off 3G in iOS 4 but such option not available in iOS 5 so you have to turn cellar data off. Once I am in central London I manually turn it back on and battery usage remains acceptable. Finally, to sum up, do a setting reset or restore which always helps, check your iCloud sync (I bought the 'system activity monitor' from App store), WiFi sync, disconnect cellar data if you are in a poor 3G coverage area and then sit back relax enjoying your iPhone Disclaimer, I'm a normal Apple user not a clever engineer or scientist I'm not responsible for any mis-leading and/or finding/directions suggested from this post, nor for inconclusive findings on the poor battery performance. Any further doubt check with your local Apple Store specialist.