I think it depends almost entirely(see thierry13's post below) on the teacher you get. There are a lot of good schools, but there's also a lot of good schools with a few top-teachers, who teaches the top-students, while the rest of the students are there too keep the school running and they get mid-class teachers. At least I think so... that's what I've heard.
I overheard some violinists discussing Manhattan School of Music and the Juilliard School, one of them clearly pointed out that the atmosphere in Manhattan Sch. was much more inviting, and you got to know your teacher "better", if you know what I mean, while in Juilliard you were either the best, working very close with the greatest teachers, or you were a part of that big filling-mass....
I dunno of course if that is true. I'm not going to state anything. I've never been to any of the schools, so don't take these rumours as true. Actually I would like somebody to argument against them, see different points of view in this topic? Again, I don't want to step on anybodys feet, I'm just forwarding rumours I've heard.
Best regards,
Joachim