We'll be staying at the GF this summer for the first time. We have stayed at the Contemporary (tower club 12th floor) and at the Poly (standard, garden, lagoon and concierge). I can't comment on the GF, but between Poly and Contemporary, I'd pick Poly. Being directly across from the MK is awesome. We always watch the fireworks from the beach at least once a trip. The Grand Ceremonial House holds all the public areas, restaurants, gift shops etc. Being walking distance from the TTC is great. I've been to Hawaii and the feel of the Poly is very close. There's nothing like the smell of the lobby.
The Contemporary does offer a great game room, The Food and Fun Center which is a good place for a snack at midnight. The walk to/from from the MK is a plus especially when the monorail lines are long. If we stay at Contemporary again, it will definitely be a tower room. Garden rooms seem too removed for me.
One thing to consider, we tried to get a room at the Contemporary for this summer's trip. Looked at a suite, concierge, regular tower room, and couldn't get one. Shades of Green, the military resort is currently closed for rehab and the military is being given rooms at the Contemporary instead. It is harder to get a reservation there right now. I don't know how much longer until SOG is done. This could play a factor in your decision.