We stayed at AKL and GF 12/27-1/4 and though I like AKL more, I thought the GF was much more convenient. I know others this AKL has great bus service, but it was far from that during our 4 night stay, 12/27-12/31. We never waited less than 20 minutes for a bus (our usual wait was about 30 minutes), and several times we waited over 50 minutes for a bus!!! These 50 minute waits were at different times of the day, so I can't say mornings were better than evenings. (In fact, we arrived at MGM on NYE at park opening, which was 8am for general public, though we were waiting for the bus since 6:35--it was not only NYE, but an EE day for MGM so we planned to be there a little past 7--imagine the mobs fighting to get through the gates at park opening for fear the park would close it's gates!!)
When we switched to GF on 12/31, we immediately saw a change. The buses were so much better and the monorail made things so convenient. The Poly would have been even better as we would not have had to transfer monorails to get to Epcot.
We have also stayed at CSR and it is huge! It's a great resort, but I'd go with a monorail hotel during that busy time of year as it made a huge difference in our trip.