To add on about buying experiences, I've never had a bad transaction on here in 14+ years. I am selective about who I deal with but feel confident that the board policies make it a great place to get some great deals. I've had some sellers that over grade but never enough to make me request a refund etc... Those sellers that do that on a regular basis, I just don't buy from anymore.
Side note on the PMs. Maybe the seller doesn't have the option turned on, but I have all PMs sent to my email. Sometimes it's easier to read the email if at work/in meetings or out and about.