Once assembled, this rack proves to be extremely solid without being too heavy. The casters roll quite well on a wood floor, makes it very easy to reposition my gear rack as needed.
Size is good for smaller width units. I have put a 37 key keyboard, a large desktop synth, a pedal board etc on the shelves without difficulty. Note: very small units may require you to adjust holders or get clever. I do not think a full sized keyboard would fit well though.
I found assembly a little tricky - in particular, getting the security clamps locked into place took me some time to figure out. The solution I found was to loosen the clamps enough so that you can shift the ends of each shelf bar up and down a little until I could get the tab into place. Still, worth it for how solid it is!