What’s the difference? A number of things, including what can go in the routine and how the cheerleaders look.
The biggest differences is that high school and college cheerleaders can have any skill in their routine as long as it is not against the rules, where on All Star there are multiple levels and the cheerleaders can’t go beyond the skills that are in their level. Some high schools will have two girls throwing fulls while the rest of the team has a back handspring. As much as their team has the ability to do, can go on the mat. For an All-Star team there are certain skills that are allowed to be put in the routine and the better the cheerleader, the higher level team they will be on.
A smaller distinction between the routines is that almost all high school routines have a cheer where they stop the music and all shout in unison. All Star teams sometimes have a cheer, but it is not emphasized as much and the music goes right through it. Occasionally the words of the cheer, if the team has one, will be in the music.
There is a large contrast between how the cheerleaders present themselves. Often times if someone goes to an All Star competition they will see a sea of red lipstick and glitter. Even for younger girls there is a full face of makeup, they are there to put on a show. On the other hand, a high school team may not have more than some foundation and a little mascara. College could go either way. It definitely depends on the coach no matter what kind of team the cheerleader is on.
The uniforms can differ as well. High schools go with the more modest route, mostly mid-thigh skirts and long sleeved tops, although it depends on the school. All Star teams have more variety; some teams wear skirts and some wear spandex shorts, some have full length tops while others have crop tops. Since All Star is privately run and not through a school they may have more leeway.