The holder proved to be just as stable as the first impression suggests: Since wobbles and clatters nix.
All joints are very tight set, which was already criticized here by one or the other.
At first I thought well, I would have the nuts slightly loose. But when I then attached the screen (24 inch PC screen), this has been fixed by the lever, one has thus on its own: The strain on the back is not large, and everything can be nice move smoothly, so I that had nothing to adjust the screws.
Only negative: The screws for attaching the monitor are far too long, I had another use. I could also use the mitgeliferten spacers, but that to me was the screen too far away from the bracket.