I used to be a Vimperator user, then Pentadactyl user, and after that, Vimium user. In all three cases I eventually gave up on 'em because they kept breaking and like you said, they got in the way as much as they helped.

But on the Vim-emulation for IDEs front I would like to send a shout-out to JetBrains for the IdeaVim plugin. IdeaVim combined with the CLion IDE, also by JetBrains, and language specific plugins, help me so massively much when I work on any project that spans more than a handful of files.

In several cases there are projects that I work on with ease in CLion that I could not imagine trying to do with plain old Vim, and there is no other IDE that I have enjoyed using as much as CLion, not even by a long shot.

I have nothing but good things to say about CLion and of JetBrains. Unless they do something drastically weird to CLion they likely have a customer for life in me.

IdeaVim is not a complete emulation of Vim, but it is a complete emulation of the parts of Vim that I use and expect, so I am very satisfied with it.