I have a TyTN and the first one I had had a couple of sticky keys (E, Space, P) so I exhcanged for another one. This seems more stable but still have one half-sticky R (need to press it harder than the others to make sure it registers). I think this is more of a hardware problem (quality control of the keyboard circuit board).
On the other hand, I have noticed that the device is not as stable as my old K-Jam. There are occasions where it froze. I've turned it off (completely and not hibernate) altogether on the plance and after I landed, I took out my phone and the display is on full blast with the phone frozen at the today screen. Somehow it turned back on and drained quite a bit of battery. This happened on another occasion but is difficult to repeat. Also, there are the occasionaly freeze/hang up that requires a reset.
I hope an impending firmware upgrade would solve some of these.