I still have yet to have a reboot. I did reflash a fresh image about a couple of weeks after I got it (unlocked, rooted, went back to stock....normal testing the waters with a new device kind of stuff). I am still running the CM 10.1 nightlies and leaving the device on 24/7. I have bootlog uptime installed and the only time that there is a break in the log is from flashing a new nightly release every two days (I'm not gready and have to flash every one).
I have heard the device is far more stable with custom ROMs. Here is my Boot log Uptime log running stock 4.2.1:
9:33PM, January 23 - 0d 11h 23m 14s - still running
9:11PM, January 23 - crash - 0d 0h 21m 48s
12:12AM, January 23 - crash - 0d 20h 59m 29s
11:55AM, January 22 - crash - 0d 12h 16m 19s
9:33PM, January 20 - crash - 1d 14h 22m 49s
5:20PM, January 20 - crash - 0d 4h 12m 43s
3:38PM, January 20 - 0d 1h 40m 32s
1:39PM, January 20 - crash - 0d 1h 59m 11s
4:36PM, January 19 - crash - 0d 21h 2m 31s
11:21PM, January 17 - crash - 1d 17h 15m 2s
10:58PM, January 17 - 0d 0h 22m 16s
10:14PM, January 17 - 0d 0h 42m 31s
7:41AM, January 17 - crash - 0d 14h 33m 26s
8:44PM, January 16 - 0d 10h 55m 12s
8:41PM, January 15 - crash - 1d 0h 2m 54s
9:05AM, January 14 - crash - 1d 11h 36m 6s
4:35PM, January 13 - 0d 16h 27m 11s
1:39PM, January 13 - crash - 0d 2h 55m 54s
4:15PM, January 12 - crash - 0d 21h 23m 44s
6:47PM, January 9 - crash - 2d 21h 27m 58s
2:20PM, January 8 - crash - 1d 4h 26m 37s
7:33PM, January 7 - crash - 0d 18h 47m 22s
6:23PM, January 7 - crash - 0d 1h 9m 39s
7:48PM, January 6 - crash - 0d 22h 35m 37s