Serif fonts are harder to render on low DPI displays, such as nearly every Windows machine in existence. I really wish that high DPI displays would take over the world, but I know how difficult that will be. I'm even having trouble myself, I'm in the market for a new Chromebook and I found one with a very nice 235dpi display. I can get it for $400, but my wife is giving me grief because similar ones with a crappy display are available for $250.