The best summer festivals/camps vary depending on what you're looking for. There's Eastern Music Festival, Brevard, Aspen, Music Academy of the West, Roundtop, Texas Music Festival, Tanglewood (BUTI for highschoolers), Banff, Yellow Barn, Wabass, SIMF, Pacific, Verbier, Schleischwig-Holstien (sp), National Orchestra Institute, National Repertoiry Orchestra, Karr Kamp, Chataqua, Domaine Forget. Those are ones I can think of off the top of my head, and they are all of completely different calliber, so you'll definetly want to do some research. There are also plenty of others that I'm sure I'm forgetting.
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What imput (how competitive compared to others, overall experience, etc.) does anybody have on Music Acadamy of the West, Eastern Music Festival, Texas Music Festival, and the Norfolk New Music Workshop at Yale?