Well, aside from the shiny key issue (all of the keys in the alpha cluster of my Das are practically mirror-finished), the quality is comparable. I personally feel the Filcos have a slight edge on quality, but it's very slight. I also prefer more rectangular keyboards, so the bump on the DK to accomodate the USB port kinda irks me, but then again, it's a USB port. So that kinda makes up for it.
As far as the keys getting shiny, I've noticed that they both (meaning Filco and Das Keyboard) will start to get shiny after a few weeks of use. I'm on my keyboard all the freakin time, so YMMV. Apparently if you want to minimize the shininess issue, you should get a set of PBT replacement keycaps. I'm still waiting on mine, so I can't comment on whether that's true or not. One thing I will say though is that I've noticed that my red board's caps wear significantly slower than my blue board did or my brown board is. It may have something to do with the lightness of the switch and that I'm not pressing down on the cap as hard.
As far as noise goes, I don't have any pinging issues with my boards, except for my left control key on my brown tenkeyless, and even then I have to concentrate to hear it.
Overall, both boards are built like tanks. You can't go wrong with either one. But I can guarantee this: You'll want another one soon