Again, this is not an Internet Explorer problem, it's a Microsoft issue that affects their entire recent product line: Windows 8 (and all third-party developers that use its code in their applications, be it Apps or Desktop ones), Office 2013 and of course, IE 10. God knows what else. Let's at least hope they are aware of it...
True.
The problem is even worse in Office 2013 than IE10.
I tried Office 2013 on Windows 7 and still the font rendering was terrible, so I had to roll back to Office 2010.
At least IE10 on Windows 7 is usable, although still not as clear as Firefox and Opera.