My son (15) PREFERS All Star Music over every deluxe and moderate we've stayed at (Poly, Dixie Landings/Riverside, Coronado Springs). He's stayed there many times since he was 10 and says he thinks the theming is better there than at the more expensive resorts. Kids typically are not impressed by the "luxury" aspects of the resorts and, in my experience, like the obviously Disney-related stuff best -- which is what the All Stars do best!
I will also say that it has been my experience that the bus transportation to and from the All Stars is better than that from the more expensive resorts -- it seems to run more often.