Firefox 4 is a great browser, as it runs smoothly and is faster and more secure than Internet Explorer. The new layout is very efficient and saves browser real estate. The only thing I personally don’t like is the appearance of the new orange button on the top left of the screen.
 
There is a great add-on called App Button Clear that fixes this by making the Firefox button transparent.
 
This is how the button looks after the add-on is installed: