Dell XPS 13 Developer Edition (comes with Ubuntu pre-installed). The best part, though, is that Dell wrote a bunch of drivers for the hardware that got integrated into the main Linux kernel--I've installed over 10 distros on it (not all at once!) and on every one of them brightness, multitouch gestures, etc, worked out of the box.
I've got the XPS 13 standard edition (max-specced refurb was half-price of the dev edition!) and it's been nearly smooth sailing.
One difference between the dev and std editions is the wifi chipset - 6235 in std, 6230 in dev (and some reports of the AR9462 in others). The wifi was practically unusable for me until I manually disabled power-saving on the wifi interface.
Also had a couple of instances where the machine has dropped into a coma (even on full battery). Usually after rebooting or suspending. Quite scary when it happens, since the long-hold power button trick doesn't always revive it. It usually comes back to life later but I wish I knew what was causing this.
Also have to run the battery all the way down to 0% (the point at which the HW forces a shutdown) and charge back up to 100% every couple of months else the calibration goes wonky.
From what I understand the XPS 13 standard is exactly the same as the standard model without Ubuntu preinstalled yes (except that it has a windows key as opposed to a linux labeled key)? The developer edition is not available in all countries.
So you don't have to obtain the Dell drivers separately? They are included in ubuntu 12 onward?
I don't believe all of the drivers were actually merged upstream. According to reports that I've read, if you don't create a recovery disc, and try to install stock Ubuntu 12, you are in for a nasty surprise as half the hardware doesn't work. Installing drivers without a working network interface, sucks.
I did a stock reinstall of Ubuntu 12.04 shortly after getting the laptop and everything worked except for one brightness tweak which took me <5 minutes.
