I'd also say the Filco w/ browns isn't necessarily quiet. It can be quiet, if you're careful to not bottom out the keys, but I can easily hear my wife typing away from upstairs if she's racking away on it. I could hear her racking away on the old Microsoft Natural too though. The Natural was maybe a little quieter, but I think it may be the pitch of the keys bottoming out on the Filco that causes the sound to be more noticeable. I had an ABS M1 with black ALPS copies for a short while before this and it was horrendously loud.
I originally thought that Filco was too quiet for my tastes, but I think that was simply from coming off off the ABS M1 and a Dell AT101W.
I honestly probably would've gone with the Cherry G80-3000 if I purely wanted a board to type on, but I really wanted to profile and looks of the Filco. That said, I wouldn't have any trouble using the Filco at work - nobody complained about the ABS M1 though.