Spirit is a nice little shop in Northampton, Ma. Bought from them a long time ago. Recent purchases from Audio Classics in Vestal, NY were all completely first class in every respect. Would buy from them again.
Dealers That Sell Large Volumes of Used Gear Online
I have purchased from a couple such dealers, and my favorite so far is The Music Room in Colorado. They have been entirely professional, and most importantly, their gear always arrives well packed and in better shape than even their description would lead one to expect. Their prices are reasonable, they are not gouging. I'm not affiliated, just a happy 2x customer.