This mic works well for me. I had few expectations, considering the price, but I wanted to 'get into' ribbons.
Overall, the sound is on the dark/mellow side, but it was an advantage with a guitar combo, that ended up sounding wonderful and grungy. When close-micing a quiet male voice it also performed surprisingly well, sibliance and breath was well under control - and the mic responds very well to EQ. It's figure 8, of course, so placement needs to be be carefully considered, and some form of damping of the rear may be helpful.
This mic requires good pre-amps, because the output is quite low and the gain needs to be raised accordingly.
The RB 100 may not be the most open, crisp mic in the world, but to my mind it - and other ribbons, I suppose - brings a welcome alternative to the super crisp large diaphragm condensers.
Build quality is absolutely ok, the shock mount works well (just too bad that it doesn't fit in the box). I like the retro styling, and that it is not overdone.