I will start with the few common things.
are you aware of any Dirah or Dorm that goes to sleep before 1 or two AM?
would you send your child to any yeshiva if that yeshiva also has bad (very bad students) only because there are some good ones too?
so what if the child is good, this doesnt mean that the child will not get influenced by some friends.
Astrix, stop with this Kedusha thing, you know that this is not true, no one goes nuts and the kedusha thing is not a factor. its the Hefkeirus!
i have been to lots of Diras, with Talmidim from famous YEshivos.
I have gone together with Friends who learned day and night, MOST of the them changed (to the worse)
you are being naive, this is a fact, I HAVE seen it, there is a huge Hefkeirus.