I follow a certain number of ruby-related blogs and have noticed regular of calls to use Vim as an editor, usually with claims of unbridled productivity to follow. One one hand, I see the appeal: I use a bunch of UNIX tools and scripts in my daily work-flow and it makes sense to use a editor that works inside my terminal. I have tried a few tutorials, screen casts and what not, but I have never felt really comfortable. Something has always been off. I always assumed it was due to the big learning curve others talk about.
On the other hand, when I switched from TextMate to Sublime Text, there was almost no drop in productivity. Part of it has to do with similar functionality being mapped to the same keys, like command-t. However, I believe that there is more to it.