Android customization Galaxy Note
Only devices with NVIDIA Tegra chips in them can be completely restored to factory conditions. 

When you root your phone, the warranty is void, and there is no sending it back. 

You can Back-Up a ROM and before booting, wipe the phone's ROM and restore one of the backed up ROMs. 
Backing up and restoring is very time consuming, though. 
You would only want to do that so you could perhaps have an AOSP ROM, a TouchWhiz ROM, and perhaps a CM9 or AOKP ROM as well-- 
Trust me, you'll be too busy flashing new updates to worry about switching between backups. 

Head over to http://forum.xda-developers.com/forumdisplay.php?f=1346 for the low down on the rest. You can never read enough, really-- 

The different ROMs will be under the Development section.