I am good with both. I use Vim on a daily basis and I've used every Visual Studio from 6.0 to 2008. I love Visual Studio's debugger and file management, integration of a wide array of tools for adding references and configuration and code generation and endless other things.
But when you're talking hard core file editing where you just wanna jump all over a few files and produce more than two thousand lines of code per day, Vim really shines. You have to be good at it though, it's not for the faint of heart. you have to remember how to set marks and use them and make use of all the registers and write regular expressions fluently. You have to know how to select paragraphs and matching brackets and find / jump to any part of the file very quickly. All this takes time to learn and it could be argued that it wastes more time than it saves. So I think what it comes back to is that it's a pleasure to use because it doesn't get in your way or freeze, and that makes all the difference.
For any Vim noobies reading this, I have four tips:
1. change your caps lock key into a ctrl key and use Ctrl + [ to get out of insert mode.
2. use v and V to enter visual mode and marvel at how convenient it is when you don't want to think about all the crazy ways to select text.
3. use ctags and read online guides for how to jump back and forth throughout your project by integrating with it.
4. check out command references online and use it a lot, it took me about a year to get decent with it.