Some minor problems : Some keybindings are missing though, like opening/closing sidepane and full integration of navigation with containers. Copying a block of text sometimes copies all the text in one line, this is a bit annoying when copying a code snippet with particular tabs and lines organization.
I do not know how to live without it! This is the first add-on I install on any Firefox instance I work with. Great Vi/Vim like keyboard navigation and shortcuts which are missing from the Standard Firefox... These functionalities are what any proficient user needs.
It's not perfect, but it's damn good and getting better all the time. 5 stars for recreating so much of the Vimperator experience, for the thoughtful workarounds on the constraints imposed by the new Firefox APIs and for the continual improvement.