Firefox 4 will be a big change when it comes to how we all interact with the browser. One slight change that people either cheer or boo is adding tabs on top of Firefox, rather than the current position most of you use today.
So why has Firefox made the jump from the current tab position to putting tabs on top of the browser? Alex Faaborg does a great job at explaining thing here:
If you are not a fan of having your tabs on the top of the browser, do not think of changing browsers or not updating just yet. They make it clear that Firefox’s user interface is still totally customizable, so you can drag your tabs back down to the Firefox 3 position if you fear the user interface change.