This thing is pretty sexy and amazing, but I’m probably not going to install it because I think it might get in the way when I need mobility rather than sexy. For my desktop, though, it would be awesome.
I’ve seen people using it in class and it does look awesome. The SpeedDial thing (also known as bookmarks for those of us living in the past) makes it 10x better. You’ve got your open tabs, you’ve got your bookmarks (tabs you would want to open at some point), all in one place. Now, because I haven’t tried it, it’s entirely possible that this thing is horrible to use. Maybe you’ll love it, maybe you won’t. But I just thought it was nice.
Also I hate every single change they make to the look of FireFox. All of them. From 2.0 to 3.0, every random change from there that broke themes I was using, the incompatibility of Personas with themes (Personas became so popular that stupid people came at risk of screwing themselves up), and now FF 4.0 is like completely meh to me. Moving tabs up to the top of the window? Blah.