One thing I haven't heard others mention is fun. The better I get with vim, the more fun I have applying my skills to work efficiently.

I also love that I can use it with a phone keyboard and still remain highly efficient. Being able to SSH into my server on the go and not be terribly hampered in my admin and editing is pretty amazing.

Ubiquitous, powerful, flexible, lightweight, fun: it's a pretty good mix of positives in the tradeoff for vim.