Blurry font on Firefox, Opera

Try using full hinting in Firefox.

Firefox doesn't use the system font hinting settings, so you have to enable it manually...

  1. Remove existing link for 10-hinting-slight.conf -> ../conf.avail/10-hinting-slight.conf...

    sudo rm /etc/fonts/conf.d/10-hinting-*.conf
    
  2. Add new link for 10-hinting-full.conf -> /etc/fonts/conf.avail/10-hinting-full.conf...

    sudo ln -sv /etc/fonts/conf.avail/10-hinting-full.conf /etc/fonts/conf.d/
    
  3. Restart your computer for the changes to take effect. (Loging-out and loging-back-in may also be sufficient).