#1 will always be POP Century ..... but

the SkyLiner greatly impacted the price point. I originally moved mostly offsite but last couple years have stayed AllStar Sports often (just got back, and return in August).
POP Century has more landscaping, lusher landscaping, a lake and nothing feels on top of each other. Began staying there regularly a long time ago, requesting lake view rooms (for the price of a value) and looking at the ghost of POP's Legendary years. The food court is bigger and more comfortable to eat at. There are two quiet pools, and the Bowling Pin pool is our favorite. But the main pool and kids area is still nice and doesn't feel overcrowded. I just stayed at POP for a week in May (in a new room), and just stayed at AllStar Sports last week ~ so with a close comparison, POP really does stand out as nicer and above the AllStars.
Art of Animation has the plus of three AWESOME pools and incredible theming and decor around the property. LOVE walking about taking photos and enjoying the great imagineering. It has the SkyLiner as well. The downside for ME is the Little Mermaid rooms seem a bit farther but mostly disconnected from the main hub. We don't need a suite at Disney prices.
AllStar Sports is our most recent go to and I am surprised Iike it. I think it has the best pool of the AllStars, with the whole boardwalk and surf theme around it. The footprint is fairly tight and so even if I get stuck with a farther room, the walk is still do able. The gift shop is apart from food court so you have access to the drink machines even after hours. I've probably had around 15-20 stays here and it works out fine for us. We are mostly park centric but this main pool is appealing to us as well.
AllStar Movies is fun, the most Disney themed of the AllStars. Love the 101 Dalmations and Toy Story sections are so cute, great for photos. I think Love Bug feels a bit removed so I wouldn't want that area. We haven't stayed there much, I think Sports setup works better for us (we usually book standard).
AllStar Music is our least favorite resort overall and unless I was boxed in a corner and needed a suite there, I will not return. We've had multiple bad stays there (safety, to location, to noise, to food court issues) and as someone who travels alone with my disabled son, I don't feel safe there. One side borders on large parking lot with laundry facility there. Often large 18 wheelers parked there. We've dealt with police called to nearby guests issues more than once. The layout is awful with the hub being at one end and standard rooms at other. The walk can be very long and the resort is very dark. I don't feel safe there and I'm a city kid.