I'm intrigued, what's your beef with iTunes?
A guest came through here one evening and said the iTunes is practically designed to hose a Windows computer with extra processes that aren't used or installed in the Mac OS.
OK, personally, I won't go near anything related to Apple. So, your mission, should you decide to accept it, is to determine the veracity of the guest's statement.
It made a lot of sense to me, but I confess that I wanted him to be right, and didn't bother to look into it, since I would never install it in the first place.
Amazon used to allow the purchase of MP3 file, without any proprietary software installed, and it was a dream. Then I was dumb enough to order an "Amazon Instant Video", and all of a sudden, I had a bunch of crap running at startup, and immovable video, dripping with DRM. You can in fact, transfer these videos to one more computer, but then you have to install the same crap software, with the same crap results.
So,Redbox it is for me (*), along with purchased CD and DVDs or Blu-Ray.
If iTunes if it serves you well, by all means enjoy it.
(*) I understand that you are in the UK, and don't know the DVD rental landscape you have to deal with.