I use one (2015 model), it's ok. The 2560x1440 screen works well (using 1.5 scaling) with unity, a bit less so with cinnamon, as it Cinnamon only supports integ

I use one (2015 model), it's ok. The 2560x1440 screen works well (using 1.5 scaling) with unity, a bit less so with cinnamon, as it Cinnamon only supports integer scaling. Chrome has a scaling flag that is independent, that's a bit extra work. I regularly connect an external 4k screen over DP, works fine and runs at 60Hz. The touchpad is ok, but wish it was larger and dealt with palms better. Over time I adapted and now am careful to not touch it while typing (or maybe some update fixed it). I use an older Ubuntu version and there are a two bugs - it doesn't always lock when closing the lid and the touchpad is sometimes disabled on wakeup. Switching to a terminal (ctrl-alt-1) and back reenables it. Overall, I'm happy - great keyboard, decent HiDPI screen and all in a very light machine. 16GB RAM and longer battery life would be nice, but I'm happy with the weight tradeoff.