My vote is GF. The resort is incredible, especially around Christmas time. GF has the best dining options at a resort, in my opinion. 1 stop from MK on the monorail. Since the construction, there's a lot of hype around Poly right now, and its a nice walk from GF. I think Boardwalk Inn is a little boring, but the fact you can walk to EPCOT from there is a huge plus. I've stayed at all 3 several times (coincidentally same time you will be staying there), and have no complaints for any of them. For most people it all comes down to a personal preference.