If you know vim I'd assume you already know the answer. If you know vim and don't know the answer, I guess vim just doesn't work for you. But for many others, it does. I'm not going to enumerate what's already covered in endless blog posts, SO answers, books, IRC logs, and .vimrcs.
That doesn't really answer the question, does it? The other poster made an assertion about VIM being more efficient. I would like to get a list from him (or her).
Funny enough, not one person is stepping up to the plate to justify and quantify the claims that vi/vim are/have "highly efficient text-editing capabilities".
Numbers. Not statements or links to the manual. I care about data. Show me a project that got done sooner and better because of the use of vi/vim and you'll have a point. I propose that not one person can make that claim and that the popularity of vi/vim are purely tribal.
In this show they demonstrate, among other things, how tribal behavior can be taken to an extreme. It is very hard for some to go against group behavior. They show one example of a guy in a room that stands up when everyone else stands up and he doesn't even know why.
To some extent I believe that some of these tools are like that. You work in a shop where the hot programmer swears by vi/vim and you adopt that without challenging any of it. Very soon everyone is playing the same tune, facts be damned. I happen to be one of those people that does not engage in crowd behavior. This can be a blessing and a curse. I never bothered to spend months on vi/vim because every time I used for days or weeks (out of not having other choices) I came out of it with the distinct idea that the whole thing was just short of lunacy. In the context of the project that needed to be completed these tools offered no real advantages. You are not going to impact the bottom line in any measurable way.
Put another way: If you took two kids that knew nothing whatsoever about computers or programming and set out to teach them. One is taught with modern mostly-GUI tools with "conventional" keyboard shortcuts while the other has to use command line and vi/vim. Both of them have to complete the same project. The vi kid would be absolutely smoked by the other kid in no time at all. No question about it.
OK, how about a second project. Maybe not smoked, but no significant gains would exist out of the vi camp. Programming is far more about things that have nothing to do with text editing. Projects are not late or buggy because of good or bad text editing tools.
I'd still like to see someone quantify the gains offered by vi/vim over the course of a project.
Furthermore, "the other has to use command line and vi/vim. " seems to be confused. Using vi style editing does not really have anything to do with the command line (though it frequently does, that is out of choice, not necessity).