I upgraded to Windows 8.1 yesterday and the problem got MUCH WORSE! I didn't even notice the blurry font until 8.1 and now it's almost unbearably awful. I have a 2-month-old Toshiba Satellite laptop, touchscreen. I'm going to try reinstalling display drivers, see if it makes any difference. When I upgraded to Windows 8.1 last night, the touchscreen stopped working (!) and I had to reinstall the touchscreen drivers.
I'm a professional Microsoft developer, and I'm so pissed off at them right now.