I've been using 191.07 for exactly 3 weeks now without any problems. In fact there have been some performance improvments in some games.
Prototype ran even better the 191.07's for me.
But, it's not really worth taking a chance with anymore - especially given my BSOD situation from last week. I didn't know what the heck last week caused my BSOD, but the only thing I recently changed on my system was upgrading to the 191.07's.
190.62 was also a decent set but 191.07 outperforms it in some titles I have, most notably Fallout 3.
I never had problems w/ the 190.63 - I just uninstalled 191.07's and reinstalled the 190.62.
In my case I am using Windows 7 x64. Could it be a problem with the x86 version of the driver?
Good question. I don't know.
The EVGA boards are still trying to figure things out w/ these 191.07's.