The rooms, services, and amenities are practically identical at each All-Star Resort. The only real differences are in the "decoration"; for example, the wallpaper, building fixtures, pools, and the oversize "icons" are themed to the particular resort. Building arrangement also varies (the farthest rooms are in Country Fair at Music). Each has one shop and a food court; again, the only real differences are the styling and name on the door.
I'd suggest you make a selection based on which "theme" most appeals to your personal taste. I've yet to see a shabby room at any of these resorts. Movies often fills up before Sports and Music, which could make the decision for you. I have also heard about Music having fewer children, but my experience there is in the summer, and I didn't notice this (though even our poolside room was quiet).