I've never once had as many problems with a driver as the 27.10s gave me. I couldn't even make it through one day without the urge to nuke them from my system overcame me. 🙂 Lock, reboot, lock, reboot, lock, reboot (repeat as needed). Went back to the 23.11s, all is fine now. Of course, your mileage may vary.
FYI: Anyone with Medal of Honor may want to try the 23.11s if they haven't already. I went from the 23.10s to the 27.10s, neither ran MOA as smoothly as I'd like with maxxed settings, switched to 23.11 and it's running smooth. I will say that Tribes 2 seemed excellent with the 27.10s though, so I guess it all depends on what you need them for and if they are stable on your system.