I use Jaspers 4R-150B for housing all my current home studio. In the lower rack lies a 28kg Korg Triton Extreme 88. In the rest racks lie four sound modules, a mixing desk, Midisport 4x4, a 21" monitor, a laptop and a Mininova leaving enough space for even more.
The stand is unbelievable light and rolls on its wheels with no difficulty even when loaded. It is also very stable.
Assembling is easy and quick and doesn't take more than 10 minutes. Mind though that you should spend some 15 minutes more before you do it in order to be sure that you assemble it right and as your needs impose. Expect no help from a manual or from Jaspers website. In the box there is only a generic photo and a couple of words that don't give any serious hint.
The holder stoppers are lame. They are from plastic (why Jaspers?) and although they can be easily replaced there are no spares in the box you receive. Two of them came to me broken and Thomann has no stock of them so they have to call Jaspers. You will receive some spare adhesive felts which will come handy sooner or late since there not of the highest quality. Two of mine came damaged.
Pros:
Lightweight, easy assembly, sturdy, good quality wheels
Cons:
Plastic (!) stoppers, a bit pricey, no assembly instructions
In general I think you won't regret buying it although a few minor changes would make it even better.
In the link below you can find a very interesting article of Keyboard magazine and also some assembly help:
http://www.keyboardmag.com/accessories/1187/jaspers-keyboard-stands-the-solution-for-stacking/29460
