The difference is pretty much top D-I Publics have two lines that can play, C.C. have three and Prep have four. The top 10-15 D-I Public kids, the top 15-20 C.C. kids and the top 25-30 Prep kids are interchangeable.
Prep plays longer games (18 vs. 15 minute periods), generally have more up-to-date systems and coaches and I beleive they find more games. They somewhat take care of the players as far as advancing them to the next level and getting them together to play on teams in the off-season. Where as the Public and half of the C.C. coaches don't get it when it comes to moving the kids to the next level (exhibiting absolute fear when it comes to communicating with Junior teams and College scouts) it is expected the Preps have their ducks in a row.