I had the same issue. I bought both the black rubberish version, as well as the clear plastic one.

The Black one broke within a week. One of the tabs on the top part broke off.

Tried the crystal one and after a couple of days realized there was a jagged bit of plastic sticking out underneath the top section. When I was opening an closing the keyboard it was scratching the textured finish away on the space to the right of the keyboard. Not a big deal as that will wear off over time anyway... still rather crap though!

If you think the space above the top line on the keyboard is bad already, these cases cut that in half! I'm not using any form of case, or even a screen protector now... just a lanyard. I'm not too bothered if it gets a few scratches. Important thing is it gets used! Do you work for the n900?, or does it work for you?!