I have stayed at POP but the last five stays and our next stay (2/24/16) will be at Music. Here is why.
POP has 2880 rooms and Music has 1604 rooms. Chances are there is less crowding and noise at Music due to 2,552 less people. I get that number by taking the extra POP rooms and multiplying by 2.
Music, I have found, has never let me down when it came to cleanliness, noise, accommodations in the restaurant or using the front desk, and I have found the staff to be extremely friendly and helpful. So much so that I email several of the ladies from the staff regularly. As for the bus situation, don't worry about the so called sharing problem. The All Stars only share in the mid day times when there are smaller groups waiting for buses. That adds an additional 3-5 minutes on the bus if you have to share. Besides, with the extra 2500 guests at POP waiting for a bus, you do the figuring on how long you may have to wait. I too am a park person but my wife and I always return to Music in the afternoon for pool relaxation time. We are in our 60's and enjoy the mid afternoon break. It is always restful poolside and we cannot complain about noise or a full pool for these times. Hope this has helped.