I also have a Das keyboard and it is really awesome. (Also, I think it's the best looking keyboard I have ever seen--very minimalist.) However, I think you have them backwards--the "silent" version has the brown switches and the normal version has the blue switches. I also have the ultimate silent version and it is not really silent--it's just quieter than the other version. You still get a satisfying noise when you use it.
I've been really satisfied with it, and would definitely recommend it to anybody looking for a nice mechanical keyboard.
You are of course right! I have a brown, not a blue! Not sure why I was thinking about it in reverse - oops.
Well, mine is quieter than other keyboards I've used, eg a Dell keyboard as long as you don't bottom the keys out, though I do get the occasional loudish click when the keys snap back, usually from the space bar, though if I slow down when typing I can make it almost completely silent (obviously thats not normal typing though).
 I did have a Saitek eclipse a few years ago that was quieter.