The AoA offers more immersive theming than All Stars, and it has Pop within a short walk, yet ASMu Suites do have a few things to consider, which might make them your first choice.
ASMu suites are in the preferred section of the resort. None of the suites are in the far reaches of the resort. Some of the suites at AoA are a longer walk, and as of now proximity to the main building is only a request.
ASMu Suites have four beds, Queen, Full pull out, Twin pull out, and slightly less than twin pull out. This can be useful if you have people who prefer not to share a bed. AoA has three beds, Queen, Full pull out, Full Murphy bed which is also the table.
While each room can legally hold six people, plus infant, the sleeping arrangements are different.
The $300 differrence could get you cabs back and forth to the parks avoiding a long line for a bus every day of your trip and still have enough money for other fun perks!