friend of noodle,
If you can, get in touch with parents who have sent their children to one of these schools. Other parents can be a great resource when trying to choose a school, since they have already gone through the process of deciding which private school to send their child to and they have already had experience with the academics, the faculty, etc.
It is always good to supplement any advice you get with some research. Although rankings and reviews should be taken with a grain of salt, they can play a helpful role in the decision making process. You can check the Noodle school profiles for All Hallows High School and Cardinal Hayes High School that give a description of the school and its curriculum. You can also find information about Cardinal Hayes High School and All Hallows High School at Private School Review. Finding reviews and rankings from many sites and different people will help you to get a more realistic perspective of the school, but be on the look out for reviews that seem biased or unfair! The best approach is to match hard data with conversations you've had with people who have experience attending or working at the school.
After you check out these sites, you may want to do some more digging around online to develop a well rounded picture of the schools you are considering. You might want to look into other schools in the area to see how your schools of interest stack up against other near by schools — you can always use Noodle to search for nearby Catholic high schools in NYC.