I have stayed at Pop and Music and we have now returned to Music for our last 6 trips. Here are some numbers and you can make your choice.
POP has 2880 rooms while Music has 1604 rooms. At 2 persons per room, that means when the resorts are full, Pop will have 2552 more people using the pools, eating breakfast in the morning, trying to use the buses to get to the parks. I also found the staff at Music to be especially nice. Check out me with the girls from the gift shop. We email eachother throughout the year. My wife and I look forward to our week at Music every year and wouldn't change for anything.