I've used Proficient for escrow. They take detailed pics and measurements, and will describe any roll outs with measurements as well (e.g., if there's a roll, it won't be described in credit card units). They will not verify that the cue is what it is being sold as. So if you are buying an un marked, unknown cue some guy says is a Balabushka, that's not part of the deal. They will, however, let you know if what winds up in their shop is different from the description and pictures. Once both parties OK the deal, Proficient ships the cue to the buyer, and the funds to the seller. As the buyer, I sent a bank check in an envelope so there was no possibility of a dishonored check - if you are selling, I recommend you request that as part of the deal. Shipping prices are the responsibility of both parties. Proficient handles the packing - they don't mess around on that front.
It put both me and the seller at ease given that I bough it from a total stranger over Facebook and we both wanted some level of security. I recommend it if you are shelling out $$$ for a cue from someone that has no prior history or is not an established seller or buyer.