Modular cases can be eye-wateringly expensive; the Doepfer "low cost" cases are probably the best balance of value and features. The only significant difference between these and the standard cases is the finish: these are unpainted and lack the metal corner-brackets that protect the larger Doepfer cases. For installation in a studio or home studio, they're absolutely fine, and I'd much rather spend an extra £10 on a tin of one-coat gloss paint and a throwaway paintbrush than many times that on a pre-painted case!
The screwmounts in the rack strips are at fixed intervals, which is a little less convenient than the sliding nuts used on some cases and skiffs; you can't just loosen the screws and slide modules along -- if you need to re-order your setup, you'll have to take everything out and start over. But again, that should be balanced against the low cost of the case.
All in all this has been an ideal starter case for me. I've ended up buying two to house a steadily expanding modular system, and they're good-looking and rock solid. Recommended!