Since I've mostly used the classifieds. I can only comment on those. I've sold a few parts, and bought a few. My friend has sold a bunch of parts.
Sadly I've had one bad deal, only one. I made a deal to buy a Ghia. I talked to the guy a few times on the phone, told him I was looking for a solid car. I gave a deposit. Then drove 2-300 miles, with a rented truck and trailer to pick it up. It was dark out when I got there, and the car looked Terible, it looked like it had been painted with a roller. Supose to be new paint. and the floor pans. Also said to be new. Looked like the person that put them in had no experiance, and no welder. Rust in no so good places. I looked at the pictures a 100 times. Even talked to the guy. Didn't see anything. After I got back the spots I saw on the real car I could barely see in the pictures, ONLY because I knew they were there. Didn't get the car. The deposit I gave him was more than the car was worth. I think he was asking $2000 or something for it. I saw it later, and he either sold it or kept it.
Oh well. Live and learn. Hope this helps.