Love it, but there's a bug... Rated 5 out of 5 stars
Granted, the bug is in FF 1.5 (haven't tried 3), if FF is the default browser and another application opens a browser window, a super-minimized window opens along with your browser window.
Otherwise, I do like it. To those of you who say it's useless, keep in mind that not all of us like tabbed browsing. I like the multiple stimuli, I function much better with it. I'm perfectly able to focus only on the windows I'm concerned with at any given time. Not to mention if you ever have to describe something in another window, or copy text from an image or video, you need a windowed interface.
I really do appreciate this effort. With Firefox overtaking IE in popularity I feel us window-style browsers will eventually be left out in the cold.