I tried out the new Twitter layout using Firefox 3.6.6. Unfortunately, most of the page (the exception being the navigation bar at the top) would not display, and I had to start up another web browser (Opera) to get the page to properly display so I could go back to the old layout. As to what I thought of the layout when it properly displayed on Opera, I liked how much more detailed it was, but I could certainly live without it, since I would rather use Firefox for browsing, and do not want to open a separate browser for one page.