I can offer this piece of information about Pop... when using the buses that take you to the parks, the Pop Century bus makes only one stop - the park and the resort. The shuttles for the All Star Resorts stop at all three - Sports, Movies, Music... I was imagining last week how incredibly crowded those shuttles must be when the Pop ones had people standing every trip.
Besides all of that, I did really enjoy Pop. We just returned a few days ago, and it was a great place. I would request to be in the 60s building. We were very close to the "Hippy Dippy Pool," and it was great. Have a great trip!