My multi instrument playing son (guitar, piano and trumpet ) is now playing french horn in the school band and his instructor says he is ready for the double french horn. Great for him BUT, we can't rent a double french horn like we are the single we have to buy.

Anyone here have band instrument rent / purchase experience and recommendations? I am leary of buying a brass instrument without seeing it, unless it is reputable company with lots of feedback or company like Musicians Friend.
Any places you can point me to appreciated.