That's not quite true. The Livna packages have had a number of bugs that the official NVIDIA driver packages never had. Most of it has been file omissions.
Granted, that can happen, any additional packaging can always introduce its own problems (although, to be honest, I cannot remember ever falling over any myself).
All I can say is in my experience I have had less problems during the time I used rpms, to the time I didn't. For me the convenience of the rpms outweighs the possibility of a few additional packaging bugs.
My point was more to clarify that they aren't completely different drivers, as Karl seems to think.
Chris