I recently replaced my wife's aging MacBook Air with the Samsung/ARM Chromebook - she much prefers it. It doesn't overheat, nor require frequent restarts. But she has a Masters in CS, and works from the command line, so let's add to, "computer-illiterate people" , "..and people who dont want to spend time nursing their computer".
Fully-featured web IDE; supports Ruby, Python, Go, and more. You provision a box to do your development on.
I know Unity hasn't, and Gnome 3 (my favorite) has pixel-doubling support on the way, but if there are any others or if you've been able to optimize an X WM to be readable and polished.
https://github.com/appsforartists/pixel_webdev
All I use it for is Sublime Text, so things more-or-less look great for me. The problem with Linux is that there are multiple ways of doing any one thing. So, just because Openbox and Sublime can handle high DPI doesn't mean your run-of-the-mill KDE/GTK app will.
I've got my setup scripted here:
Chrome and Win8RT are the only OSes that are good for an ARM-based notebook form-factor, and the ARM chip is necessary to make this device not suck at this end of the cost spectrum.
That and frankly, I think we're all sick of supporting Grandma's windows machine, so getting computer-illiterate people onto a "web-only" device is great.
I won't buy one, I don't need one, but I can see the niches it fills.