[WhiteDragon]

It's pretty clear to me what's happening with the fonts. The new rendering just doesn't use font hinting (aligning the font with the pixel grid so it doesn't look 'blurry') at all, or doesn't apply it as much. Windows is notorious for using a huge amount of font hinting, and often ruining fonts as a consequence. Mac on the other hand is much less extreme about it. I imagine the v6 fonts would match up with how Mac renders fonts decently well. This is really a matter of taste.

I don't know why things are changing size though, that should be fixed.