I used Vim casually so I'm not an expert. I understand that it'll take a while to master it. But compare to netbeans where you can navigate Ruby code quite fast (shortcut to method implementation, class implementation, project browse, auto-suggest, etc), why would I want to use Vim when I have to find the proper plugins (not just one, but a few) before I can be productive (assuming they can do what I mentioned above).
It's nice to have an editor you know how to be productive in when you start using a new tech.
In an average workday I'll touch ASP, JavaScript, Sass, CoffeeScript, PHP, and Ruby code. When I use VIm, I can use all of the shortcuts and things I've learned over the years to manipulate text. I know how to manage projects, find files, etc.
That's a huge advantage. Having to learn Eclipse to do Java or Visual Studio to do C# adds complexity cos you have to learn the tool and the language.
So yea, I totally get it. This goes for TextMate or Emacs too.
The portability of Vim-the-application and thus the portability of the skills to use it are a big reason why I put in the time to learn it (same applies for Emacs). I can just as comfortably program locally, on a remote server or on a friend's machine.
Even when we were building version 1.0 of the software, there aren't too many text editing as opposed to navigating the code tree.
Isn't dynamic/scripting languages like Ruby and Python produced way less code than Java? (Hence, less typing again).
So this is why I don't quite get the group of people that swear by vim.