Rated 4 out of 5 stars
Wow, this is great! Almost perfect. If it weren't for this fix, I would have gone back to FF 3.6.
The fonts are now sharp and clear. The only problem is that the spacing between letters in some fonts is off completely. Some letters in a word are really close to each other, while others show a large gap (as if there are two words instead of one).
Just look at this page: the two letters "s" in Password are quite far apart when the font is set to GDI Classic. It's a little better in GDI Natural, but with Natural some other letters and numbers are wider than they should be.