Maart, mechanical disc systems can be excellent, but of course low end ones can be, well low end. Any well designed ones, e even old ones like my avid bb7s work great, but other newer designs are easier to set up apparently.
To me it's a non issue as I only have to take a few minutes to adjust pads after thousands of touring miles, so not a big deal at all.
but yes, good shimano hydros at reasonable prices are excellent also and self adjust.
so it depends
and I don't want hydro on my tours, in case I have to get my bike put on the roof of a truck or in a trunk and a housing gets damaged.... so for me mechanical is more robust and I've ridden heavily loaded in mountains a lot and they work fine.