I stayed at both Pop and All Star Movies this past Fall. First time at the value resorts. Both resorts had similar accommodations. Both resorts had similar decorations and level of landscaping outside. The bus service to ASMo was to that resort only, at the time I stayed there. However, if you noticed an All Star Music bus leaving the parks, you could take that and walk a very short distance to All Star Movies. I did this one night, and I think almost everyone who got off the bus at ASMu walked over to ASMo.
Pop differed from ASMo with quite a bit larger gift shop with many more selections. Same could be said for Pop's food court which had more food choices, and an espresso machine (important to me, maybe not to you). Also, from Pop I could cross the bridge and go to AoA's food court, where I had some marvelous food choices available no where else. Walking around AoA was an absolute thrill, and you could see the kids and parents were loving every inch of the new property. At night it was nice (but a tad cool in Nov.) to walk along the lake at Pop and look out to AoA across the lake. All Star Movies had no water feature. Not sure if any All Star resort had one.
I had a fine stay at each resort. If it's about a real tight budget, I'd choose All Stars and you would have the same great time as Pop. If you want an enhanced resort for the items I listed above, I'd choose Pop.