I was disappointed with a recent experience with SVC.com. Ordered some power supplies (2) and a few 3-4pin adapter cables. A few days later I received a note that the 3-4pin cables were out of stock and the whole order would be placed on hold, unless I wanted to pay double shipping for separate items. Not a big deal, but, still sucked...
A week after that, I received another note that the power supplies were NOW out of stock and my order would be on hold. That t'd me off. If they were in stock when I ordered then they should have been set aside for me for when the rest of my items came in. Nope.
Summary: They do not have real time inventory. At least they cancelled my order w/o hassle.
Update: In the past I've received items rather quickly, but, I also hadn't (apparently) ordered any items that were out of stock. So, just be aware that if they don't have it in inventory it may be a while and they don't seem to have a proffesional way of dealing with that scenario.