Here is our experience with the Pop buses. (Granted, the resort was COMPLETELY full)
In the morning, fine. Got out no problem.
In the middle of the day to go back to the resort, fine.
Late at night, TERRIBLE!!
We often close the park down folks and stay for late EMH and often are in the park at least an hour after closing. Then we wander to the buses. For the most part when we do this when staying at All-Stars, the bus lines have dwindled down to almost nothing and we get on an empty bus rather quickly.
When we stayed at Pop, on several occasions late at night there was STILL a long line at the Pop bus stop and it took awhile to get through the line on a bus.
You see, Pop has only one bus stop at the parks, whereas All-Stars has three. So at busy park closing, they can split them up and get folks out of there faster.
Pop is the equivalent of 1.5 All-Stars, but only has one bus stop. It just takes longer to load folks.