I've bought and done trade-ins over the past few years and been very pleased with the outcome.
But, I dont think I'll be doing business with them again. I purchased a pair of Purist IC's and asked them to inspect and test the RCA connectors. The transaction went well, but after a few weeks a connector broke, then a connector broke on the second cable. Purist's price for installing new RCA's is very high. Now I'm stuck with these expensive cables.
The other reason is due to an insulting offer on a preamp I had for sale. I sent pics and received an offer so low that i laughed. I emailed back showing the prices on the used market and they wouldn't up their offer. I eventually sold the preamp on Audiogon for 3X the amount. I went to TMR first assuming I could make a fast sale at a fair price.
The problem with buying some items from them is the unknown provenance; eg, amount of owners unknown, age of item unknown.