ViEmu shoutout: Its impressive. It can't be easy to make Visual Studio play well with the Vim input model, but ViEmu manages it flawlessly. It even has a pretty smart method of managing Visual Studio's keybindings. If you want to go in and out of "ViEmu mode" it will disable and enable conflicting keybindings for you.
If you've ever been interested in learning Vim, the ViEmu developer Jon has created some really nice "graphical cheat sheets" that make learning Vim quite a bit easier. He has also written some good articles on why Vim is so nice: "Why, oh WHY..." and "The Vi input model". Those articles will sum it up better than I can, so I recommend you check them out if you're at all interested.
But that's not going to stop me from throwing in my own 2 cents. What makes Vim great?
- It is comfortable to use
- It lets you say what you want to do
Another example is the "t" and "f" keys which are like mini searches. "t" means to and "f" means find. Type "fa" and it will move your cursor to the next occurrence of the letter a on the current line. "ta" will move your cursor to right before the next occurrence. "T" and "F" go backwards. Again this is nice because it replaces a string of keyboard actions that might look like "ctl+right,ctl+right,right,right,right" Not only is that simply more keystrokes, it also requires you to move your hands around and perform some control key acrobatics.
Both of these examples demonstrate how Vim is comfortable. The second also demonstrates how it lets me say what I mean. Instead of using a combination of meaningless movement keys to get to the letter a, I said "go to a." At first blush this doesn't seem like it would matter, but as the Vim commands become second nature you can start talking to your editor at a much higher level without thinking about it.
It lets you stay focused on what you're trying to do to the text and not how to do it.
Its important to note that these are just the simplest examples I could think of. Vim has A LOT more to offer. Its also important to answer this question: will it make you more productive? Maybe, I don't know, its hard to say. Does it matter? If it makes you more comfortable and less irritated (ctl+right,ctl+right,ctl+right,ctl+right,ctl+right...), isn't that good enough? After all, I'm going to guess you spend a lot of time typing into that editor of yours.
Finally, if you're interested in giving Vim a shot I would certainly encourage it. It does have a pretty steep learning curve, but the cool thing is you can still do all the "notepad" style editing things you're used to. So you can learn it at whatever pace you want to, one feature at a time. If you're in Visual Studio, ViEmu has a 30 day trial. If you're in Eclipse, there is a Vi plugin. And if you're just editing text there's always gVim.