Kubuntu 13.10 has been installed on a Lenovo T431 ultrabook, with a couple of compatibility issues but generally working quite well. Ultrabooks are an Intel developed specification or brand for high end laptops that are lightweight. There’s no ultrabooks that are preinstalled with Linux yet, but that doesn’t mean you can’t install your favorite linux distribution on it.
Kubuntu 13.10 mostly worked out of the box, but on portable devices power consumption and battery life are pretty significant concerns. The Windows-only power configuration tools allowed setting how much the battery was allowed to be charged up to, as a measure to increase the number of charge cycles and the lifespan of the battery. These settings were saved onto the firmware of the battery, and there wasn’t any way to change it other than using the proprietary configuration tools.