I personally love the Poly, the convienant transportation (monorail at resort & easy walk to TTC) and beautiful atmosphere did me in. Other than transportation, I would think it would really depend on what kind of atmosphere you are looking for. I live in the "wilderness" as it is so I'd rather have a tropical feel when on vacation.
The Beach Club and Boardwalk are also very convienant (BCV only a few weeks away!). Would you be staying in a stuido/villa? If you would be in a
DVC studio or villa you would also get a kitchen or kitchenette. Also you can walk, or take the boat, to Epcot and MGM from the Boardwalk/BCV area. Which parks do you plan to spend more time at?