The tabbed browsing just takes up space in the browser window. I have a task bar for a reason. Web pages load slower than in IE6. I don't like that if you click on a link in a page that is loading, Firefox doesn't do anything. It wont let you open the new link until the page has finished loading (or you rirht click -> open in new window). Images load a lot less quickly than in IE6. I also don't like the menu bar. Even when I have everything moved up to the same line as File/Edit, etc, it's about 5-10 pixels wider than in IE. (thats a little thing, but I find it annoying)