I experience the problem, not just in iTunes. And it is most noticeable when you scroll slowly. I saw this on iPad 2 and 4. They both had iOS 6.0.1 installed.
I must've gotten lucky, because I've not seen shuddering on my iPad 2 or 4. My iPad 2 is still on iOS 5.1.1, and I plan to keep it that way indefinitely. My iPad 4 is on 6.0.1.
If shuddering affected my iPad 4 even on slow scroll, I'd take it back to Apple.