Well lets see in my DD's gym PrepOp teams are of 2 types Compete and Non Compete. The Non Compete is more like an advanced rec class. The compete team is a team but they only meet 2x's a week for about 2 hours a day. They do routines like optionals where they all have their own routines but there is less time commitment, less cost and honestly from what I have seen of the compete prep op team it seems to be girls that are older and because of age wouldn't be invited to the regular team. It seems to be a program that is more than a rec class but isn't as committed as the regular team. I've seen several girls who didn't advance in level on the regular team move to prep op. The Meets I've seen well the judging seems to be more relaxed and high scores are given for routines that would never make it in the regular team. Bent legs, lots of falling, skills only average.
I've also seen girls who have lots of talent and should be on a regular team that are there because the families can't afford the regular team route.