The rails arrived and they look better than the pictures here! After reading one of the reviews, I fully expected some rough edges around the nut holders from the machine cuts, but instead I got a shiny, polished, smooth set of rails from top to bottom! It looks like Thomann really takes those reviews seriously, so they are improving the quality of their products.
I also ordered the 5650 cage nut pack to go with it, just to make sure everything fits nicely (and it does).
I recommend these rails, especially for home-built racks!