Ok, I'll balance things up here (or just provide an alternative point of view!).
I like the MK resort area. Particularly I like staying at WL, but would not be averse to staying at the Poly or perhaps at CR. I would not stay at GF... too stuffy for my liking (yes, I have visited it).
What I feel is that for the price you pay for some (nay all) of the Epcot resorts, there is very little privacy and all the resorts are backed onto each other. I like having a little niche that is my resort. Also MK resort areas are quieter, and you don't have a lot of tourists hanging around that don't actually stay in the resort as you do on Boardwalk. Last time I was there, there was a big party/karaoke kind of thing in Boardwalk and it just took over the place: I couldn't imagine trying to get some sleep in the hotel with all the noise.
On the transportation issue, this one always seems to puzzle me and maybe I am missing something here, but when I visited the Swan and BWI a year or so ago and then tried to get back to MK I firstly waited ages on a bus, and then it stopped at EVERY other Epcot resort. I didn't think at the time that it was particularly good service for such expensive resorts. Obviously you can walk to Epcot, but I wouldn't think you'd always want to walk to MGM. Also the Friendship boats are quite slow to load and move LOL so it could be a thought just going to the park! In contrast we found WL launch to MK a breeze and quite zippy actually.
I think I've prattled on for long enough to attempt to balance the argument. Good thread by the way!
John
Oh, and we're three adults (or BIG kids)!