I go with them pretty often for both business and personal purchases. While their prices aren't always the best, they beat others frequently enough (and when they do, often by a large enough margin) that they're on my short list of places to check before making a purchase.

Do watch the shipping charges though. Usually they're reasonable, but every once and a while the charge will be strangely high for a small, lightweight item. That can be a deal killer.

On the other hand, I'll often receive items from them the day after ordering, even with cheap-o ground shipping. Of course, depending upon where you live, that may not be happen for you.

The only customer service problem I've had with them was relatively minor and related to a purchase order for several ATTO Celerity cards. During the time my P.O. sat in limbo in my employer's purchasing department, ATTO changed the part number of one of the cards by one digit. (I suspect to reflect an updated driver CD, as everything else stayed the same.) Provatage wouldn't just change that line of the P.O. to the "new" ATTO card, so I had to submit a new P.O. The world didn't end, but it delayed the setup of my SAN and was mildly annoying.