Ok, so inconsistency appears because Microsoft didn't have the time. They may have also kept ClearType for compatibility with other programs. What happens when they move completely on grayscale? Will Firefox, Chrome and the rest programs appear the same way as IE does?
Now, my main question (and suggestion to Microsoft) has to do with the viewing angle that almost corrects the issue in many cases. Could Microsoft give us an option to calibrate the font rendering? Do you see any difference when viewing your monitor from different angles?
I've uploaded two photos of my monitor from a low and a high viewing angle. Actually, they don't help because they are far from real life but it's obvious that there is a difference. In my case the low viewing angle is better (not clear in picture).
see bellow
https://skydrive.live.com/redir?resid=6494BBBF4713A74!784&authkey=!ADDqUXF2LKbntR4
https://skydrive.live.com/redir?resid=6494BBBF4713A74!783&authkey=!AGZO7L_NiDWOFSo