UVM is like any other school when it comes to partying: it all depends on who you hang out with. So make your friends carefully :-) Despite being a big school there are lots of communities and it's easy to get involved and make friends. People are friendly (and so are most professors).
The place itself is nice, Burlington is a small city, but it's got everything you could need. The campus is large, but there are buses if you don't like walking. It gets cold and windy in the winter, with only a little sunlight. But don't let that scare you away.
We don't have any huge concerts, due to the lack of huge venues, but there is Higher Ground (www.highergroundmusic.com/) which always has performances going on. Also right on campus we have a thursday night coffee house which hosts local bands. And every other week is an open mic night when anyone who wants to preform is invited to do so!
The mountains might sound small, but snowboarding (or skiing) here is a completely different experience from anything out west. It's not all gliding and powder, our little mountains make you work! But it's great fun, and all the resorts have college discount seasons passes. Jay Peak (www.jaypeakresort.com) even runs a free shuttle to and from the mountain on weekends (good since freshmen aren't allowed cars)
I hope you consider UVM, it's a great school with great people and a great environment. Good luck finding a school!