Whenever the "font quality" thread breaks out, there seems to be a three-way tie between the people who vastly prefer ClearType, OS X or Linux fonts.
Personally I'm with you -- font support on Linux gives me headaches to try and use.
But I installed the latest Gutsy alpha, and font rendering seems to have taken another substantial step forward. To my eyes it's still not as good as ClearType, but it's beginning to get into the level where it might not matter as much.
Firefox fonts on Linux still melt my retinas, but there you go.