I use this on my desktop to house four different racks, and it was very easy to put the units into the rack with the supplied screws. It is a very sturdy unit and weighs quite a bit more than I expected (note that it comes assembled, no IKEA manuals needed).
The drawback is that the screws can be slightly flimsy to get in place, and the unit isn't quite as black as I expected it to be (more of a grey/brownish hue to it). It's nitpicking but it would have looked even better had it been as dark as I thought it would be.
Either way, it does what it should for a fair price!