Right, my two peneth.
I have had TERRIBLE battery life since 'upgrading' to my 4S from my 4. Quick synopsis:
Restored from my iPhone4 backup running iOS 5. Immediately noticed poor performance - battery wouldnt last a day. Found this page and some other pages with possible solutions:
1. I have no exchange server email accounts.
2. I disabled EVERYTHING from notification centre.
3. The 'set time zone automatically' setting DID have the GPS on continously - but disabling this hasnt helped.
4. Installed a system monitor and have following findings:
a) Page Faults are going up at around 250 every 2 seconds. I realise these aren't 'faults' but surely there shoudlnt be a release of memory this often! They total over 4 MILLION now!!
b) In the system log there are 2 recurring themes. First is that there seems to be a recuring apple DEBUG of powerStateWillChangeToGated but more alarming is a WARNING roughly every 15 seconds of UserEventAgent [12] 'Unable to cancel system wake for 2011-10-30 **:**:** +0000 IOPMCancelScheduledPowerEvent() returned 0xe00002c2' This seems to be more worrying as it indictes there is a failure to stop the system waking.
Without doing ANYTHING on my phone it has used 100% of the battery in 18hours - no phone calls, no texts, no internet!!!
Ive now had enough and am going to restore to factory and see if the phone behaves when it's started from fresh on iOS5.
Apple, I am VERY dissapponted with your performance on this. If it is just the fact that you cannot start from a restore from a previous iPhone then please let us know. But otherwise the OS simply is not fit for purpose. I may switch back to iOS4 on my old iPhone - could get a week standby from that!!!
Good luck apple - you dont have long to sort this out until you lose a LOT of previously loyal customers!