I'm running Linux Mint on an Asus Zenbook (basically a cheap copy of a MBA). The only real issues I'm having is that I haven't worked out how to get the laptop to sleep, and there's a weird order of steps I have to take to get an external monitor working. Oh, and the keyboard isn't great.

After a few months I've got used to the problems, but I do miss OS X. (I'm more than happy to give Apple my money to make things Just Work.)