we stayed at the RPC at the GF last Fall and this January we stayed regular GV at the Poly. I would have to say our favorite is the Poly. We rent a car and love the convenience of the Tahiti building which is a quick walk to the TTC and also there is a small parking lot near it to self park at. One thing I did not like at the GF was the guest self parking lot - it was quite a distance to walk so we chose to valet park. I prefer parking ourselves so we can hop in the car whenever we want. We have a 3 year old son and the convenience of getting on the monorail (his favorite ride) at the TTC was great, especially going to Epcot. It took a little longer to get to Epcot from GF.
We didn't get to try the Poly's pool but did enjoy the GF's a lot. Both resorts are lovely. The maid service was good at both. Nothing special at Poly (we were celebrating his 3rd birthday and noted it on the reservation) - nothing ever left in room for his birthday (didn't expect anything) and no towel animals.
At the GF we got several towel animals and maid service was excellent. Not sure if that was because we were staying concierge. But, I'm sure you could get a special maid at either resort.
You can't go wrong with either resort; just depends on what you are looking for.