Personally, I am a fan of POP. It has a lake which I like, access to AoA and newly renovated rooms that look very nice if the one bed plus pull down works for your family/group. Not sure how I feel about the upcoming Skyliner.
That said, we have had many very nice stays in AS resorts. I like that they are smaller. We enjoy the theming, especially of ASMo. rarely had shared buses, but it didn't bother us when we did really. Only 3 stops total. If the budget worked better for the AS resorts, I would be fine with staying at any of these again. I would prefer either ASMo or ASSp unless staying preferred or in a suite, however. The layout for standard rooms in ASMu puts some rooms a bit far to be my choice.
Enjoy whichever you choose. Both POP and AS are great options.