Each individual All Star resort is smaller than the Pop. So at the All Stars you have less people trying to use the common spaces like the pools and the food court.
It is true that the All Star resorts do sometimes share a bus, but not always. And in my experience never leaving the parks at closing time. Even when they do share it is not a big deal. You can easily walk from one All Star resort to another, so it maybe takes 8 minutes to stop at all 3 All Star resorts. What is nice too is that if you just miss your own resort's bus leaving the parks at night and another All Star bus pulls up, you can just hop on it and be back to your resort after the bus ride and a very short walk.
And while the Pop building itself is newer, the rooms at both the All Star Music and Sports have been recently refurbed, making them fresher than those at both the Pop and the Movies.
I stayed at the Music in May, and the Sports in November. And they were both great resorts.