The big back button on the top left is a nice design feature. In general, it is clean, fast and pleasing to the eye. I think they did an excellent design job both technically and visually. My plugins work (for the most part). The only thing I see a flaw (and it is really minor) is the spinning dots all the way on the top right. I am staring at them now. Whay are they still spinning? The page is done downloading. Stop! Maybe it’s an ajax call? Firebug doesn’t say anything is asking.
Additionally, that spinner is a little off center, too high. I would suggest that they put a different thing there. Or nothing. They have the progress bar at the bottom right. What is the point of that spinner? It’s too small to be seen by average users and too annoying to be ignored by anal people like me.
Why am I obsessing about a silly little spinner? Because the rest of the application is really strong and I am picking on them. A+ guys. Great work. If we are very lucky, the whole world will choose this browser, so I can develop faster.