Actually, I have been satisfied with all transactions here on Agon, both as a buyer and as a seller, although there was one unpleasant experience with a dealer (no names!) who is considered to be a jerk by many members here.
I try to both buy and sell at a fair price, never trying to "skin" anyone, and in return, I don't expect to get "skinned" when buying.
I consider this a community of like-minded audiophile "parterres", much different than a general and impersonal marketplace.