How to backup IOS7 for later recovery?

We've just bought a 5th gen iPod touch that came with IOS7.1.2. I know there are some reports of poor performance with IOS8, so I've cancelled the update for now.

How can I backup IOS7 in some way so that we can then revert back if we find IOS8 isn;t any good (or too slow)?

I done backup in iTunes but it seemed a bit quick, so I don't believe it's done a proper backup of the IOS7.

 

I thought restore to factory took it back to the as bought condition.

Anyway.... I thought if it got corrupted then it could be restored to the same as the backup condition, it'd be no good having apps restored that didn't work on a particular IOS if it only put the new one on. It's working fine on IOS7, I don't want to go to IOS8 and find it runs like crap.

 

I'd have said this was an iPod touch specific problem rather than IOS7 problem. The information's about backing up the IOS from the iPod not 6/7/8 specific.