With a freshly installed ubuntu 12.04 on my dell xps 13,
$ uname -r 3.8.0-32-generic
On another laptop,
$ uname -r 3.2.0-55-generic
I wouldn't care if not for that low brightness bug https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1163720, that is only fixed with 3.2 ... and which makes the laptop pretty useless.
The only hint of reason I can think of that could explain that kernel is that I had to execute
boot-repair on my xps (because UEFI mess ...) which asked me to execute some commands .. forgot which ones .. I know I added a PPA ..
OT: I tried 13.10 on my xps, low brightness bug also, plus some indefinable display issue that I can't even google or ask for since it's indefinable.