In a much delayed update, here are my thoughts on Ubuntu 12.10 on the Dell XPS 12. I've been running it for approximately 3 week now, so I believe I have a good idea about stability, battery life, and the like. In short: it's fantastic.
For easy comparison, you might like to refer to my update of Ubuntu 13.04 on this same laptop first.
This worked perfectly out of the box. The installer was a little slow to react (given the specification of this laptop, and my previous experience with installing Ubuntu), but not enough to warrant an investigation.
No complaints here, either. In original Ubuntu style, it 'just worked' and I was one happy chappy to discover that. The resolution is simply perfect, text is incredibly crisp (in all applications) and the overall performance is more than suitable for my needs.
And this is where it starts to get interesting. The touchscreen digitizer is fine - it works out of the box (though there seems to be a hiccup of it 'getting stuck' after some extensive use) but the touchpad does not work fully. In particular, you cannot use two-finger scrolling nor tap-to-click, which is too inconvenient to ignore.
Fortunately, the solution is given in Ubuntu Bug #1103594 - "This bug was fixed in the package linux - 3.5.0-28.48". So, if you download linux-image-3.5.0-28-generic3.5.0-28.48~precise1amd64.deb, install and reboot, it should fix these touchpad related issues.
The only other minor glitches with the touchpad I found, even with the updated kernel, is the speed just didn't go nearly as high as I would have liked. CLI to the rescue:
xinput --set-prop "CyPS/2 Cypress Trackpad" "Device Accel Velocity Scaling" 50 xinput --set-prop "CyPS/2 Cypress Trackpad" "Synaptics Scrolling Distance" 8 8
Automatic screen rotation doesn't work like it does in Windows. That said, I don't like how it works in Windows: the screen must be flipped and closed for the sensor to activate (which sometimes mean putting it back in that form just to get the screen to rotate back). Lucky for us, is Dell have introduced a hardware button to lock the screen rotation, which we can use to rotate the screen:
(Beautifully, this button works regardless of the state of the screen - unlike the normal keyboard buttons.)
There is one caveat to this approach: Ubuntu treats a press of the 'screen rotate' button as the same key event as
Super+O, so you lose the ability to use that shortcut for something else.
flipscreen.sh is available on GitHub (suggestions welcome!), and it can be enabled as follows:
Very stable, with good battery life (towards 6 hours with powertop tweaks). I love it.