I ordered some stuff from there and 50% of my order (2 of 4 items) were wrong and had to be shipped back. Now the stuff I'm waiting on is out of stock. All in all though despite screwing up the order Mark seems like a decent enough guy to deal with, always answers my questions/concerns and is VERY fast at replying to e-mails. I don't think I've ever had to wait more than a couple of hours for a reply.
I would e-mail him before you order anything though to check on the stock. The website is a little out of date. (my buddy ordered some stuff a couple of weeks ago that was "in stock" but it actually wasn't and hasn't come in yet).