There was my life before Jaspers, and after Jaspers. Seriously. It helped me so much to re-organise my studio, and now I have a much better laid out space. I bought two of these bad boys and the flexibility is great.
However, it's hard to know in advance what you need until you have it, and then you can't mix and match. So if you are unsure, of course there's the 30-day return from Thomann, but even better if you can go some place where you can physically see one.
If you have super heavy old synths like a CS-80 or something (actually, that's probably too heavy, even for this rack) then you indeed need the double-supported bottom rows. But in reality probably very few modern synths would get near that weight. In which case, you can probably get by with the single-supported row.
One of my units had a couple of dings towards the top of the main vertical poles (although the packing box was absolutely fine, so I don't think it was from transport) but I couldn't be assed to complain, and I don't think it will affect the strength, so I just carried on. But maybe check yours thoroughly, just in case.
In general they are great, but the sheer AMOUNT of screwing and un-screwing you have to do to make the adjustments makes me think there must be some slightly better way to implement the various locking systems.
Also, and this is major - the construction instructions are DIABOLICAL.
But whatever, overall I am happy with the purchase and would recommend.