I own one of their earlier version of Das Keyboard, the one that actually LOOKED like IBM M model. Granted, these keyboards are very good, but I had to say, they are designed for geeks, not everyone.
First of all, the blank key sure looks cool, but it give you problem when you first sit down in front of your computer in the morning, with coffee and donut in your hand, you just want to type "cnn.com" with one hand, good luck getting it all typed correctly.
Second, the mechanical key feed back isn't always a good thing, it wakes up whoever happen to sleep around you if your computer is in the bedroom, some newer keyboard, especially logitech, tries to make their keys as quiet as possible but still give you a good tactical feedback.
I'm not sure if the newer version lost this feature, but in the version I own, each key have different weighted spring, keys you press with your little finger are lighter, the ones with index finger are heavier, maybe not a very good feature for gamers since gamers rarely put their fingers on the designated keys, but I personally find it very helpful with touch typing.
Currently, I'm still sticking with my Logitech MX5500 keyboard, just because this keyboard has a calculator built-in, and right now pretty much all I do all day long is trying to run a business, this is invaluable tool for me.