I work as a c# developer in a purely Microsoft shop.
I recently started teaching myself assembly using gas and Linux in my free time away from work. I like messing a
JaredPar mentioned ViEmu, which I've heard really good things about. But if you're really wondering what the benefits of switching would be, there's a good article hosted on the ViEmu site: Why, oh WHY, do those #?@! nutheads use vi?
Personally I feel that using gvim has been a huge boost to my productivity, and I definitely prefer it to the Visual Studio editor or SlickEdit or any of the others I've used. But as mentioned in earlier answers, Vim can be a steep learning curve. There are people who have used it professionally for 5-10 years and are still learning things about it. Vim can be a lot like perl... there are a lot of ways to make any series of edits, and it can take a while to learn the best one.