Fairly hassle-free. I have both the 2015 X1 Carbon (with Debian Jessie) and 2016 X1 Yoga (with Debian Stretch). I needed to install an extra xserver-xorg-input-

Fairly hassle-free. I have both the 2015 X1 Carbon (with Debian Jessie) and 2016 X1 Yoga (with Debian Stretch). I needed to install an extra xserver-xorg-input-* package for the touchscreen on the latter to work nicely and Firefox Aurora to get gesture support, but everything else just works. The keyboard on the X1 Yoga is sort of meh, though.