What worked for me:
I think Deelan is on the right track. My iPad 3 was messed up at first my iPhone 4S was eating its battery for breakfast.
iPhone 4S {star = ideas I like}
- initially I turned off parts of everything: notifications, Bluetooth, FB, personal hotspot, etc - this helped a little, but not enough
- reboot
* settings - general - reset settings (may have helped)
- I did not wipe it clean
- turn off safari sync on icloud
* turn off all system location services - and started turning back on only as needed
- notifications - turn off all unnecessary things like passbook/photos
- disable facebook calender sync
* turn iTunes Match on and off several times
* drain iPhone battery until it shut itself down
* update 75 apps or so
Symptoms Timeline:
Day 1 - could watch battery drain
Day 2 - iPhone warm, battery drain continued
Day 3 - iPhone charged overnight after complete drain - now working normally or better
Learnings:
- TIME - give it time - I think IOS6 had to work through some iTunes Match AND other issues and from experience this takes time
- Update apps - a lot of apps were updated over those 3 days - some may have solved some problems - who knows?
- Patience - I don't have any, but in the end letting it work through some issues was key - turning everything off prevents this
For what it's worth.
IPad 3
- I restored from iCloud backup and the issues were resolved. Battery last a long time, iTunes Match and video syncing issues were solved and my iPad is happy once again.