We stayed at the CR, Poly, and GF in January with our four children. My older kids loved all of the resorts and preferred the Poly overall - primarily due to the theming. However, while our four year old liked them all I think she preferred the GF as it was the location of Alice's Tea Party, Cinderella's Dinner, the Pirate Cruise, and the Princess Tea Party (she didn't do the cooking class or stay at any of the "kid's clubs)". She really had a great time at all of the special events at the GF (we primarily did the parks in the morning and then resort oriented activities in the afternoon).
I honestly think you can't go wrong with either resort. Overall we thought that the GF felt the most recently renovated, our room felt almost brand new, and the Poly had the best theming and was a slightly more immersive experience. Sorry, I probably didn't help but you sincerely won't go wrong with either one IMHO. Have fun choosing!