PC mag has already reviewed it. As I suspected, the ruler just comes across as lame.
If you're gonna do something totally random and arbitrary, the usefulness should at least outweigh the randomness, or you'll leave people wondering what's the point. Sorta like Ockham's Razer, don't randomly make something up unless you need it.
Why invest the extra cost (even if it is slight) if you can use that money to improve some other aspect of the keyboard. Make a higher quality sleeve for the cable, the plastic is hideous and totally unflexible. Make it detachable with a usb plug, anything. I can buy a ruler myself, for 20 cents, one that does not have an annoying thick triangular shape, and does not have the consequence of losing the tilt function of my keyboard if it happens to get lost.
Don't worry, I'm still buying the keyboard, it just pisses me off that some pretentious dumbass at a Das Keyboard meeting, trying to be different for the sake of being different, is responsible for the stupid tilt function on my keyboard.
Sorry for ranting