My mom and I stayed at Pop in Jan '07 an ASmu in Sept '07...
Pop was our first value stay and we just weren't overly impressed. We LOVED what the value resorts had to offer (especially for that price!) but just didn't get what all the hype was about Pop.
After our disapointing stay there, we agreed to try an All Star. ASmu was actually our third choice (lol) but since we couldn't get standard at movies and the pool at sports was closed, we booked preferred at ASmu and crossed our fingers.
From the second we departed the ME bus at ASmu we were in love. We were the only two people to get off for ASmu and took that as a good sign! There was no line to check-in and we were greeted by a "goofy" CM in giant Mickey hat and gloves! We were able to recieve our requests (thrid floor, dbl dbl) and the room was ready (11am during a sold out week!).
The walk from the desk to our room was 90secs and as soon as we walked in we felt like we had already recieved twice our money's worth compared to Pop. The rooms are so nicely done with the two tone walls, new linens and carpet, new furniture, and new decor. The bedding was super plush and the room had more of a "disney deluxe" feel than the motel feel at Pop.
The resort was quieter and did not seem as busy. They played pool games and music daily and an evening disney movie on an inflatable pool side screen. CMs were top notch, helpful, and friendly. The food court is showing it's age but we preferred the offerings here compared to Pop and it never seemed as busy to us.
Mousekeeping was a pleasure and we recieved towel animals nearly everyday and turn down service on our last night. Room was clean and felt like it had never even been used before. Bus service was just as good if not better at ASmu compared to Pop.
Overall... we felt spoiled at ASmu and have no desire to even return to Pop. My own concern at ASmu is traveling during a school/sports/musical/tour group time though.