Fully recommended. I have this set up as a 6 tier, wheeled, stand. Perfect for my vintage synths.
I bought the 4 tier stand with the intention of adding two more extension bars (also purchased from Thomann). Assembly requires some forethought, but is simple enough as critical pieces are marked. The instructions are not particularly helpful, but common sense will prevail.
The brackets are notched and fit in to locking 'wheels' on each tier, to physically stop the tubes from rotating, by locking them in to the connector that ties the cross bars to the uprights. That is a great design feature.
Because I changed the format of the stand slightly, I was able to use a 'spare' long tube to brace the middle-back of the stand.
And, in my case, I unscrewed the 10mm diameter threaded levelling 'feet' and replaced with 4 double rubber wheeled casters. (I reused the levelling feet bolts to affix the casters, though I had to hacksaw off the plastic feet as they were too wide for the caster, and were attached to bolts using permanent unremovable screw fittings)
The result is a stable and fully mobile 6 tier rack.