I have been testing out VimFx as well (long time Pentadactyl user). I miss being able to do ":b" and quickly find open tabs, but the Firefox awesomebar has a similar functionality if you type "%". That's what I have been using. You can see more information here: https://support.mozilla.org/en-US/kb/awesome-bar-search-fire...
Maybe my browsing style has changed; more reading and less clicking.