The Das Keyboard is basically the opposite of Apple's own typing input devices: It's glossy black, imposing and has a distinctive old-school edge, while Apple's keyboard is all lightness and aluminum. But the Das Keyboard is aimed at a particular crowd for whom the overwrought design (the company calls it "Darth Vader approved") is a selling feature, not a downside.
Das Keyboard's main draw is its use of mechanical switch keys, which make the experience of typing particularly rewarding, especially for touch typists whose fingers fly yet depend on some kind of tactile feedback. The company compares the experience to typing on an IBM Model M keyboard, a design some say has not been improved upon since. The new Mac-specific model also features dedicated deys for volume control, playback, screen brightness, disc eject, and even a sleep button for instant access to energy savings.
The built-in USB 2.0 hub should also be better than the one on Apple's own wired keyboard: Das Keyboard says it can charge and sync your iPad, which the underpowered hubs on Apple's own keyboards can't manage.
The Das Keyboard for Mac normally retails for a fairly pricey $133, but if you pre-order now via the official website, it costs $113.