We've stayed at both. My favorite of the two is Pop Century, but I really enjoyed All Star Movies, as well. There's just something about Pop Century...the bright colors, the music...it's just so cheerful! Personally, though, no matter where we stay we always have a good time.
We've stayed at Pop 3 times and will be staying there again this December. We tried ASM last Summer and hated it! It felt old and kind of yucky, I would never stay at any of the values other than Pop.
All services, food, etc. is pretty much the same for all the value resorts. But ASM has the best theming of any of them because it is Disney themed!! When I go to Disney I really could care less about a Rubiks cube or a giant Big Wheel, I want to see Disney characters!!
I was deciding between these two resorts also, ended up going with POP because I wanted to check it out for myself after reading all the positive reviews and I liked that it wasn't grouped with two other resorts. It was hard to resist the ASMovies theme though!
I much prefer the All Stars compared to POP. DH and I absolutely hated POP. He wasn't a big fan of the Values but we definitely liked the calmness at All Stars much more