I am never upgrading. I am sick of Apple's control-freakery 'nanny knows best' changing things that aren't broke, removing features, changing interfaces, changing things for the sake of 'fashion', etc. (Don't even get me started on iOS7!)
I spent a long time wrangling iTunes - figuring out its 'behaviour' and configuring it do what I want in the way I wanted it. It works, now. Version 11 broke some of that and I was faced with a different interface/missing functions. The differences may have been small or trivial to some, but frankly I just don't need the hassle. Why should I be forced to adapt my behaviour because some Apple-employed, contemptible, 'developer' (good grief!) thinks s/he knows best what I need, and that things I used before are no longer of use to me? I need no further 'features, and if I do then I'd like them to be additive, not replacing existing features I also still use.
Same applies to much other Apple software (and many apps in the App store).
One day they'll break my ability to use this version of iTunes on whatever hardware / operating system I end up with (= am forced to endure; OS version, anyway, if I stay with Mac) and I will view that event as being forced to do a 'rip and replace', and iTunes version whatever may or may not make it to the short list of things I'll consider to replace iTunes 10.