My screen is 166dpi (1920x1080, 13"), I run Ubuntu and have minor problem only with Intellij. They use their own font scaling, and it interferes with button placement on some windows.
Are you happy with it? I've had my eye on Zenbooks for a while. I was about to pull the trigger on one, but have decided to either wait for Haswell, or consider getting a (silly) taichi 31 when they come out.
I have one, I love it. Running Linux Mint 15 with Cinnamon. One thing to watch for is that some kernel versions don't work well with the function keys or bumblebee (for optimus support). I'm running 3.9.4 now and it works quite well.
edit Also, I should add that I did spend the extra money to put a Samsung 840 SSD and an extra 8gb stick of ram in here
I realise I should be able to read the docs, but I have found lots of different suggestions on how to do it, while you have successfully!