They are all nice except for Sea Braes.
West Park Flats and Villas are in the same complex if the name didn't already give that away. The flats are newer and have the same design as Belmont Flats/Heathfield. Think its usually 5/6 in each flat. The villas are nice aswel. There are 5 villas, and then between 2-4 levels (depending on what villa) in each with one 10 person flat on each level.
West Park is about a 20minute walk from campus, its great though, you don't feel like you are confined to campus the whole time. Plus there is a nightbus that takes you to campus for nights out etc. However sometimes it does get annoying, e.g if you have loads of early morning classes in the middle of winter, but personally the early morning classes in spring/summer semester make up for that imo...more time in the sun
Belmont flat are nice, the tower I'd never been in so can't comment, but it looks horrible from the outside, but it could be a 5* complex on the inside for all I know. Both Belmont and Heathfield are on campus so you don't need to walk far at all for anything.
Sea Braes is basically on Campus,but slightly further than Bmont/Hfield. You just walk up a hill and you are at the tower building/students union. Personally I didn't like the rooms in healthfield but, seemed quite dingy or something.
All in all, if you don't mind the walk go for west park, its £600 cheaper and there are double beds in most of the villas rooms (I think its most, maybe ring to double check).
But if you want campus accom, make sure you put belmont flats and healthfield as your first and second choice.