Alternatively VsVim for Visual Studio. I prefer it, although I couldn't give any reasons why.
It still fails the "Does it break flow by not implementing some feature or other?" test fairly frequently though. First thing that comes to mind is that while it has text objects, it seems to be lacking "tag" though (vit, not vi<). Which is a shame, as it's quite useful for web dev.
ViEmu even supports something like nnoremap in its .viemurc.
Case in point: My first introduction to Vim was through ViEmu.