I've never lived in South Africa so I can't really comment, however I know people who have emigrated from South Africa to the Uk and they seem to like it here.
Liking meat pies is a start
, but there is a much wider variety of food here than just the pies. Scotland does seem to have a penchant for putting everything in pies and frying food......so that might be quite interesting for you.
In terms of attitudes towards Americans, you will be fine. If anything you will find people will go out of their way to be helpful and certainly friendly.
The weather will probably be the biggest shock to your system, but that said, if you are from Wisconsin I dare say you are no stranger to the cold.
Aberdeen University will probably have a department that provides advice and assistance to overseas students and will be able to offer you information about the cost of living, the option you have in terms of accommodation, sporting facilities, and the other things you may wish to know about in your considerations.
This should be a good starting point for you:
http://www.abdn.ac.uk/study/international/