Oh yes, I've got one, and it works fine - though I can see now that I was using it a bit in a wrong way
You need to put both enlarger lamp and safelights in its sockets(all of them, that's very important to measure in absolute darkness). First I printed a test print, determined the right time to get the details in darkest shadows, set it on the timer with two rotating buttons, measure that area on the projected negative (don't forget to open the measuring cell), adjust the galvanometer to 0 with + --- - button on the lower left. Now when I measure the darkest area of the print where I want detail, and adjust the meter to 0 with time dials, I get the right exposure. But this device is capable of more - and I hope that someone from APUG who speaks Dutch would help us and translate the manual. The Dutch resembles both German and Yiddish that I understand well, but the technical texts are too difficult for my understanding, still
Zhenya