Rated 3 out of 5 stars
My fellow FF4 users... after trying this add-on (as many of you) realized that the space between letters was not quite right. I was just about to go back to FF3.6 when I tried this last option, which really solved the problem!:
Step 1 : Go to about:config from address bar.
Step 2 : Search for gfx.direct2d
Step 3 : Double Click it to set it to True.
Now, the fonts will look better as it used to in its stable version.
check this explanation on:
I have hardware acceleration ON and I didn't edit anything in Anti-Aliasing Tuner, I only did what the link said and it worked!