I agree with Rowuk. You have to make sure you're studying with the player/professor who'll get you the farthest toward your goals.
That being said, I also think the environment does make a difference. I tell all of my students that I want to change what they call "good." It's hard to know what that is unless you're in an environment that promotes/rewards an exceptionally high level of playing. Not every school is going to do that, IMHO.
I would never have known what a person could accomplish on the trumpet if I hadn't been exposed to it on a daily basis, listening to my fellow trumpeters at school. People my own age were playing soooo much better than I was, and I felt really behind. It was as much motivation for practice as was studying with my prof.
Anyway, my personal experience, my $.02.
Shermock
