Walt, if ONLY it was just a matter of cleartype. Actually, cleartype is automatically turned on when installing Win 7 and Win8 (or 8.1). All we do these days is fine tune it by picking the right boxes. No, this is a real problem that needs to be fixed by MS. I had zero issues with Win8 and immediately noticed the problem with the install of 8.1. I did a huge amount of fuzting about with cleartype, changing the display sizes, etc, all of the usual fixes. As you can see above, Chrome definitely took a hit as did several other programs.
Well, that's what I meant by "adjusting cleartype"--if it isn't "tuned" it can look blurry. Eyes, monitors, gpus, resolutions are all different, thus the whole reasoning behind a cleartype adjustment procedure. Just a suggestion...
Something I've
noticed recently that this thread brings to mind, though--when I view a page with a dark-blue/black background and light/white text, the text seems to "modulate" between blurry and sharp. It is very noticeable. I thought at first it might be my monitor acting up but now I'm not so sure. Actually, I'd be relieved if it wasn't the monitor...

Come to think of it I did not *see this* until after I had moved from 8 to 8.1... I really notice it when I open a comment thread on the front news page of this site
www.hardocp.com . Doesn't happen immediately but rather sporadically.
Edit: My box for "using one ppi-density setting for all devices" was already checked--so I
unchecked it--see what that does or if anything changes. Right now, I'm not seeing the problem. Fingers crossed.
Edit 2: I still have this problem, and I'm now leaning back toward it being a monitor issue. It's actually not so much blurriness as it is brightness--white text against a black/dark background periodically modulates between bright white (normal) and gray-white dimming. The dimming at first looks blurred, but actually isn't on closer inspection.