The issues you encounter installing Ubuntu on an MBA should be resolvable with Google and not a whole lot of effort. However, hardware compatibility and instal

The issues you encounter installing Ubuntu on an MBA should be resolvable with Google and not a whole lot of effort. However, hardware compatibility and installation issues are more or less what you're choosing when you choose Linux as a desktop OS. If that sounds like a fun project (and it really does to a lot of people) then you'll be fine with an MBA. If you want something that "just works" then, sadly, you want a proprietary OS. If you get enough RAM on your MBA, running Ubuntu in a full-screen Virtualbox window all the time will get you a Linux machine without the driver/wifi/power issues. System76 is also worth looking into, since they claim to provide a "just works" UX for Ubuntu directly on top of hardware.