Mixture of both - but as most of my guests are only spending a week they are concentrating on US (Harry Potter!), SW and my hen do is going to be Discovery Cove and stag do is Kennedy Space Center.
BUT.... we are going to Epcot on my wedding day for the afternoon and dessert party so they will all get to go to one park
My mum and dad seem to think that they dont need to go to disney as they have seen it before, but that will have been 12 years ago
I'm not too fussed - especially if most stay off site we will get some peace and quiet