Yes, to my knowledge it is a decent and reputable computer magazine. Not sure if they still do printed issues, but you could buy these even in the Netherlands (and no, the languages of these two countries are not that similar) at the time I was still buying printed magazines.c't
is the best German computer magazine out there, as most of its articles are geared towards professionals in very diverse fields of computing, electronics, (specific parts of the) law, etc. They still translate their magazine to different languages, including Dutch.
It is actually made by the people behind one of 40Hz favorite websites (heisse.de).