I am also seeing the reboots happening every 3 to 4 hours like clockwork. I didn't have the device for more than a few minutes before the first update was pushed to it, so I can't say whether or not that was related. I do have HD Widgets installed, so I will pull it off and see if that helps slow the reboots down.
I'm using BootLog Uptime to keep track of the number and frequency of reboots. If this pattern holds, my money is on some kind of memory leak... just thinking from our own development experiences. Given how much higher the resolution is on the N10, I wouldn't count out some graphics heavy apps blowing through their heap much, much faster than on any previous Android device. We'll have to wait and see.