Thanks laurim for the response - two things to get clear - I'm a UK user so Netflix is not an option and I don't tweak during rentals simply because I don't use rentals since I can't be certain of the time to be ready to view.
Not sure what you mean here. When I talk about quality being tweaked on the fly, that's automatic, not something we would do. What I DO do during a rental that appears to be slow is all those tricks to get a better connection on my end. If your country's ISP or iTunes server service is bad, there isn't anything you can do except complain to them to change.
It is the uncertainty - I've always said that bad information is worse than no information and rental users are consistently fed bad information.
I do think Apple made a mistake not making it clear what the minimum speed requirements are for HD and SD rentals. I think if they had been upfront about that, people's expectations would have been managed better.