Yeah, be really careful. I've bought a few things off them, most have gone fine (Sega Saturn twinsticks, some DC imports on clearance, a couple import GBA games, a Gamecube broadband adapter) but I ordered a "new" Nintendo N64 expansion pack from them a year or two back, and got a generic third party, obviously used, expansion pack. It may have worked, may have not, but I spent $20 (with shipping) for something I could've gotten off Ebay for like $5 (I wanted a geniune Nintendo one, and that was the only one I could find at the time). I complained to them, they said to ship it back (at my expense, of course), and they'd refund my money.
I shipped it back, and got no refund. They kept saying they were getting to it, that it may take 2-3 credit card billing cycles to show up, etc, etc. I finally had to contact American Express. The refund showed up REALLY fast at that point after Amex got involved.

Had I not shipped it back with a tracking number I'm not sure I would've even gotten it.
I ONLY order from them when it's something I absolutely cannot find anywhere else and I have a reasonable expectation it is what they claim it is.
Basically-- if they get your order right the first time, you're probably OK. If you need customer service, you are screwed.