Brass player has been to Tanglewood past two summers. Waitlisted this year. Do you think Curtis Summerfest or Brevard would be more beneficial this summer?
What grade is the musician in and is Curtis on the table for undergrad studies? If so I would think Curtis. Curtis students would be advanced so peers would be inspiring. It takes place in Philadelphia and gives a good preview of conservatory life, at least freestanding conservatory life in a city. It is three weeks- is that long enough?
Brevard also has stellar students and faculty. It is in a camp like setting where students and faculty and guest “co-exist,” which is a plus. Brevard is 6 weeks- is that too long or what your musician wants?
A student really can’t go wrong with a choice between two excellent programs like this. I would lean toward Curtis but that’s me: I love cities 
If he is interested in Curtis that would be a reason for that choice, but also check out faculty your kid will be working with at Brevard (and Curtis faculty may be visiting). It is nice to connect with teachers that your child may want to study with in the future.
Hope others come on who have personal experience with these two programs.