Yeah, I tried to buy an Athlon 1 ghz (and mobo) from them back in January (because they had the lowest price). I wait for 10 days for the package to arrive (I concurrently ordered a bunch of other parts from other retails, building a new system), and nothing shows. I call and leave a message and write an email. Nothing. I call a couple days later and get ahold of some guy that can't even speak English and ask him what's up. It takes this guy 20 minutes to navigate through the system to my order, and come to find out they were out of stock. Combined with the delay of a new order from a new cut-throat retailer, the Z-Buy thing 3.5 weeks onto my computer build time.
I don't know, maybe it was a fluke because of the large after Christmas rush or something, but I wasn' t impressed. The guy even tried to downsell me to another mobo (without the CPU) without the RAID functionality. I was like "Yeah, rokozuki, but I have 4 HD's sitting in front of me because I want a RAID-0 array." He keeps talking about how, just this time, they'll sell me the non-RAID version of the board for the same price. Whoopti-doo.
Hope this helps. For reference, the Athlon 1 gig 200 FSB and KT7A-RAID board were both pretty popular items in early January and I went through 3 other retailers before getting ahold of one that had both (microbarn.com) and shipped immediately. At least the other retailers told me up front that they were out of stock.