Some of you may be in shoes similair to mine, but i was one of those souls who went all the way through private school and now teach in the public schools.
There are two, well three if you want to count religion classes, major differences:
Parental involement at private schools is far more intrusive because of the investment being made financially by the parent. Also, many schools require activity participation as a requirement for attendence. Very seldem are private schools viewed as a "daycare" by parents as a place to drop off their kids.
The other major difference is that private schools don't have to put up with is that bottom 10% of underachievers that public schools deal with day in and day out. Often times, your tuition is forfeited if you drop out or flunk out so there is real pressure to achieve at proficient level by both parent and student.
As far as religion classes go, those are basically a combination of Sociology, Psychology, Philosophy, Ethics and Family Living classes. Sure, we went to church alot, but that was usually on game days and as a team which was good for team building.
The reality is that yes, many parents send their kids to parochial schools for their faith, but those same parents also realize that the faculty and administration get to deal with a student popoulation that is proportionally more motivated than the public schools.
The top students at at both schools are very comparable. Those students can achieve in just about any learning environment. Where I really think that private schools get there advantage, however, is with that middle group of learners who could go either way. The dress codes and stricter discipline of the private schools create a smaller population of slugs for those middle achievers to migrate towards, thus usually advancing them upwards.
I think this translates into athletics as well, which is why NCLB and school vouchers could really leave the public schools in a bind. Remember, Aquinas was 4A just ten years ago and they obviously have grown, and now the diocese is set to open a new school not far from DeSoto, Eudora, Olathe, Lenexa and to an extent, Lawrence.
All that being said, i don't think that private schools need to recruit. i believe that our government and society are already doing a good enough job of that. We public schools just have to keep setting our high expectations and continue to make the public school systems an attractive opportunity for a free and appropriate education.