Some of those questions can be answered by going to www.mi.edu
Living in LA is expensive from what i've heard, apparently MI can help find affordable accomodation. The catalogue says the cost of living of a student living off campus would be over $4000 per quarter.
Class sizes don't seem big, jonberg has been so maybe he could answer that better. Some of the footage i've seen suggests a 30 people average.
Fees just went up:
Encore program: $4,400 per quarter
Cert: $4,200 per quarter
I want to do RIT, thats $6,300!!
As for being worth it? I think that depends on what you take out of it, i need a scholarship to go, but i'll definitely do the encore program for a quarter if i dont get it.
There's a few who have been to Berklee and i think MI over at the HOD forum. I definitely know that an MI drum teacher frequents there. You might find some more answers there, or by emailing MI themselves! I actually had a dude ring my house my house and we had a nice chat! Cost me nada