My demands are met - however, I use only a "part of the functions"

I use this switch only to switch the keyboard and mouse. To this end it is working correctly. In monitor switch, I was skeptical from the outset, whether the image quality suffers. Therefore I run the video signals of my three computers directly to the screen and turn around there. This of course is a little more complicated than to do everything with a shortcut key, but I do not switches back and forth every minute between the computers and have usually a priority in operation.