Firstly, this thing a not a toy. For safety sake, only 2 people should lift the unopened package.
I was very surprised when it arrived. Plusses and minuses. The instructions had no words, just 2 diagrams. I would have preferred a step by step sequencing of optimal assembly.
The materials are very firm, and there really is quite a lot of them for the money. The casters work quite freely, and have brakes on them. The ventilation up the sides are very adequate for full utilization of the rack spaces.
The unit is best assembled without casters first, by laying it on it's back, fixing top to a side, then the other side, then bottom, and only then fixing the casters. The surfaces are held together with allen-bolts, a little fiddly though not impossible. I noticed that the casters had sharp edges on the top of them, which should have been rounded off before dispatch. So if you've a baby in the studio, careful with the fingers.
There are both stands and casters supplied with the package, and as written above, the casters have brakes on them. The casters move quite freely, so when you've a rack full of equipment you won't need a team of people to be leveraging the rack around the place.
When first assembled, the unit may sway some, like a parallelogram, however when you start putting some rack units in, it soon firms up considerably.
One of the amazing generosities of the designers was the inclusion of rack-fixing nuts and bolts... lots of them, with rubber washers. So the rack was filled some with units soon after assembly which took about 2 hours.
There are rack-unit-bolt-sockets on both the front and back of the unit so, actually, the rack has twice the accommodation space as advertised on the web page. so you can have the back of the rack filled with units also, either passive units not requiring interfacting to, or if they've got inputs or controls, you could just roll the unit out, make adjustments, then roll it back in. The top and base are quite firm, I have a printer on the top, and since I've units in the rack there is no sway out of it as the print-head is travelling back and fore.
I don't know what the quality of similar units is, but this one has worked for me, does so every day, and delivers a very high level of utility for the money paid for it.