First off, these cabinets aren't black. They're dark grey. But in a dark room it doesn't really show. That said, I expected a higher level of build quality for this kind of price; it's barely above IKEA standards.
The locking cam screws for instance can't actually be screwed in; the holes were drilled slightly too big. That means, despite the locking nuts, this unit will fall right apart if you haven't mounted anything inside it yet. Literally all of the stability comes from whatever you're installing in there. Though, admittedly, I've filled two of these units and they both feel very solid now.
Also, the melamine finish on the panels chips incredibly easy, even if you're being careful. Lastly, the holes for screwing the rack rails on to the side panels didn't come pre-drilled so you'll have to do that yourself, which is something you won't ever have to do at IKEA.