While I think that it varies from town to town and parish to parish, I'd like to speak as a mom who's been through it and urge people not to get caught up in which school has the most AP classes and the fanciest equiptment.
My kids' schools taught them self discipline, good study habits, and good values, which helped them more in college than an extra biology or french class could have. Mind you, not all Catholic schools are worth going to, like I said it depends.