Like any Yeshiva, there is a mix of bochurim. I know plenty of YU bochurim who are amazing oyvday Hashem and have hashkafos that are similar if not better than the bochurim from other yeshivas. Your daughter should treat this as any other boy and do the proper research and try it out. It is a shame that YU has come to be considered some black stain or psul when, in actuality, there are wonderful bochurim there. Some of my friends in YU are much frummer than my friends from Mir. It’s all dependent on the person, not the place. Judge a person for who he is and what he believes in and don’t generalize (usually falsely) about various places. The fact that this question was even asked is pathetic.