I have stayed at POP and Allstar Music each 4 times, and I prefer POP.
In addition to the Mickey soaps, Pop has MIckey shampoo. It also has a little shelf over the sink to put items on, Music does not. Pop has a larger t.v., and it is newer. I love the themes in the main bldg and the food court has better desserts. If you drink, there is a nicer bar out by the pool.
Parking at ALstars is better and you do not have to walk as far to your room from the lot.
I did not take the buses, but I think POP has it's own buses, while all three Allstars share, so I have heard that waiting is longer.
I like POP's main pool better than music and they have music playing outside the pool, I don't think they do at Allstar Music.
I think that both have irons and iron boards in the rooms, and both have safes.
I guess I just like the feel of POP better, and it is closer to all of the parks, except for Animal Kingdom, and DTD. Plus POP is in a differenct county, so the hotel tax is lower.
If I missed anything, I am sure someone else will cover it.