After reading these comments, I basically don't want to upgrade. I've been running Classic Theme Restorer for years to get rid of whatever the latest craze in GUI design is. I like my address bar for addresses and my search bar for searches. I love my tree style tabs. I like having a fair amount of control over my browser.

For a few years now, I've had the feeling that Firefox was actively trying to get rid of me as a user. With every new version, the user is less and less in control. It claims to be privacy-conscious, but runs Google Analytics. It tries to gather data behind my back. It's missing so many switches and toggles that I had to install a Privacy Settings extension simply to make the thing behave.