Clean 5.1.1 to 6 with backup? I have a 3rd gen retina ipad with 5.1.1 and no jailbreak.  I want to try ios 6, but with the option to go back if I don't like it.  From what I have read Apple gives no way to go back.

I don't mind if I have to jailbreak, but would prefer if I did not have to.

What is the best method for me to go 5.1.1 no jailbreak -> 6 with possibility of going back?
From what I have read on sites like iJailBreak, it is not possible to downgrade a device more recent than those using the A4 system-on-a-chip. (iPad 3 uses the A5X.) This is regardless of jailbreak status. The link above gives more technical details about the current situation.