For me the user interface is the most important. I cannot stand the user interfaces since Firefox 4 and up. Everytime I upgrade Firefox I hate so much that I keep downgrading back to version 3.6 Websites are no longer working with 3.6 and some will stop eventually. Can Mozilla make the latest version with a 3.6 interface option or go back to updating 3.6 There is a reason so many resisted upgrading from this version, and still downgrade. I am now on version 26 and not for long if I do not find a theme with the look in fill of firefox 3.6