A significant amount of work is going into both those builds but a lot more is needed. As much as I love having a multiprocess browser the V8 JS engine is the real heart of gold of chrome, and that is cross platform. Just nothing uses it besides chrome as far as I know. I do know that the next Mozilla JS engine feels to me at least (and if you benchmark different apps) just as fast. So the next firefox will be on par with speed and it will be cross platform. It will just have tabs that are not as cool.
As I recall, the bleeding-edge Safari, Firefox, and Chrome JS engines are all pretty competitive. IE and Opera are behind in public, but Opera is writing a new engine. The multiprocess structure and UI are the only real advantages Chrome has left from my point of view.
Well, FF 3.1 (or 3.5, whatever) will have an improved tabbing system, including the ability to drag tabs out of the window to create new windows, etc, but they will still lack the inherent feature that, IMO, makes Chrome a real innovator: per-tab processes. That's really the single-biggest feature that I would love to see in Firefox.
If not for a few must-have plugins that keep me coming back to Firefox, and of course the lack of Linux support, I would have switched to Chrome the moment it came out on that single feature alone.
