I've had mine since launch day and had my first (that I know of) random reboot today. I thought it might have something to do with one of the 3 new apps that I installed. It happened shortly after an intentional reboot due to the camera app hanging (for the second time since I've owned it), while the phone was sitting idle on my desk with the screen off.
I happened to check my up time just before the intentional reboot and it was at 150-some hours.
I happened to check my up time just before the intentional reboot and it was at 150-some hours.