My kiddos loved the All-Stars when they were younger and they were the best fit for our family....because are a family of 5, we don't stay there anymore as we don't find the value in two rooms or suites when we spend so little time in the room.
All Stars Sports was my sons favorite when he was 8-10ish. And yes, you can walk between all 3 but it is long, and the walk from Sports to Movies is the longest as Music is between them. But, depending on which building you are in, sometimes you are closer to other spots of a neighbor resort than your own. For example, when we were in the Mighty Ducks building at All Stars Movies, we found it was much closer to walk to the bus stop at Music than Movies where we were staying. However ALL of the kids absolutley LOVED the Toy Story building at Movies when they were little....we spent a lot of time playing in Andy's room for sure!
A nice bonus that I don't think anyone mentioned to you about sports is that it is the FIRST pick up and drop off with the bus system when it is sharing between the three. Depending on what time of year you go, this can be really helpful!!
Have fun!!
PS - the food in the All Stars is your basic food-court style grab and go type food. It has been a while since we stayed there, but if you are on the dining plan, you probably will not be eating many meals there anyway