I'm sure it's not terrible to use, but I'm not sure it's worth it for a caveman like me to put time into learning it. Sublime Text and Brackets already work very efficiently and allow me to focus on getting things done.

Of course, PHP people probably said the same thing when Rails came out. The difference is that current GUI editors are already very advanced. I'm skeptical that I would get any efficiency boost from vim (at least anytime soon).