Bought 4 post rack on casters for use in home music studio. Assembled rack is strong, fit just about perfectly when putting it together. Accessory shelves, cable support, all fit with no fiddling. Castors appear to be good for a long time and roll smoothly.
For use as a studio rack, it is perfect. If you need a rack for road work as a musician or? you would need to call the company to see if they have the typical stronger rails used in road cases, in my opinion.
I like using these server racks because of access to everything, without doors, sides, and limited access. Nice stuff at a good price.