About a week ago, I was looking for a new (mechanical) keyboard, and the one I chose is the Metadot daskeyboard model S professional silent. I chose this one because I wanted a keyboard with Cherry MX switches, non clicky switches (mainly because the clicky sound is just driving me crazy after several hours of typing). So knowing that, I knew I needed Cherry MX brown switches (tactile but non clicky). So I didn't have a lot of choice (the other choices being the Scorpio M10 and the Filco FKBN104M/EB). There was also Alps switches, but the design didn't look as elegant as the Cherry one. And of course the original design of the Model M from IBM, with the Unicomp, but only available on the ugliest keyboards ever.
So, the choice being made, I order the professional silent, with the extra Mac/Linux keycaps (when I ordered it it wasn't meant to be only on the iMac). While I'm on the topic, using this keyboard (like any other Windows keyboard) on a Mac is just a pain is the ***. The option and command key are swapped, option being just beside the space bar, and command... on the other side obviously. Just that little thing drives me crazy when I'm typing a report in LaTeX, for instance while trying to cmd+C/V, and it just displays me "ç√" instaed (I just did it again). and while using some other shortcuts involving cmd or option... I just got to get used to it.
Anyway, past that swap, and the lack of the usual shortcut on the F keys (especially brightness control, that has no substitute, unlike exposé, dashboard...), that's an incredibly great feeling. Surprisingly, it requires less force to depress a key than a membrane keyboard (it's about the same force as a MacBook alu, maybe even less. The tactile feedback is not that tactile, compared to a model M (at least from what I can remember) it also requires less force to depress the key, and it feels smoother (but probably because the one I used hasn't been used in the best conditions). The sound of the keys bottoming out is just awesome! I love it, I'd like to type again and again and again just to hear this sound. I love it, I think it's a very relaxing sound. But something weird: all the keys don't sound the same, especially the backspace key that is much louder that the other ones, probably to make you feel ashamed! Another interesting fact is that keys don't all require the same for to be depressed, for instance, the upper row requires about .45N until actuation, and the lower row (lower row of letter or space bar lower row, I don't know) requires about .60N.
For a longer story, more details (to come), photos, and a video comparing the sound of the Apple aluminum keyboard and Das model S : here. That's still a draft, and I still need a little more time to get used to use the tactile feedback (for now I just hit the key until they bottom out, but it's not as hard as it was when I began with the board.
Edit: Note that on the video the background music is about he same volume with both boards.