Agreed, and a multi-window metaphor (is that the right term -- MWM?) is one reason I bought Opera and installed it on both Linux + Win, but I like Mozilla's tabbing better and it doesn't have Opera's js shortcomings right now.

Just remember, not everyone will like every feature. Personally, I would hate that tabs feature, as I'm more of a keyboard-and-mouse kind of guy. I think I constantly have my thumb on Alt and my ring finger on Tab