As an owner of the 165mm f4 UMN, I have to give it a very high score. It is a bit heavy, but my photos with it are wonderful. The longer ones, starting with the 135mm will easily cover 24x36mm, and the working distance of 1:25 is useful in relatively close work. But please be aware that that means 1/25 life size, not 25x life size!
My 165 is similar with a working distance of 1:20 or 1:40 with an additional front adaptor. It does not really make sense for general photography, but is quite amazing at working distances form about 5 meters to quite close, at least in my experience. The things I find noteworthy are the absolute lack of aberrations and vignetting, and the very high sharpness. There is some mild CA, but very limited. Here are some shots. Please note that the last shot is of a water drop just hitting the pool of the Japanese fountain pictured before. It is an enlargement of about 1/5 of the full frame, pretty convincingly demonstrating the quality of the lens.
I have not tried it with portraits, but imagine it would be pretty unforgiving. Nor have I tried it at 1:1, but I imagine it might be quite good close up. 1600 euros is a good price if it is in good condition, but you will have to figure out how to adapt it. I was lucky that Michiyo Akiyama, who wrote the Redbook, had a number of custom adapters made, and he had one that I could buy. There are general clamp adapters available, though, that would allow you to adapt it. Flange distance is long enough to use on a DSLR.
