Originally Posted by Bah!
They most certainly are not the same. Firefox 4 uses hardware acceleration which makes the text look blurry and just basically bad. I just installed FF4 and the first thing I noticed is how bad all the text looked. A quick Google of "Firefox 4 blurry text" comes up with a ton of results saying the same thing.
Luckily, you don't need to change the sites fonts, just go into Options/Advanced and untick "Use hardware acceleration when available".
I did, but it still looks the same. Maybe I got used to the other one now. It still looks thinner, i'll google, thanks!