Well I was vimium/vimiumc user for long but I'm tridactyl user since today.
The ability to write in my prefered editor and then automatically paste it to browser is amazing also lot of features which other (also great extensions) don't have like running commands or other binds which are 100% great idea. The only thing I don't like out of box is tridactyl using firefox search instead of their own which take me a while to config.