For about 21 years I was a qwerty guy, doing a lot of COBOL (a verbose, English-like language that facilitates fast typing). It's been fourteen years since I've switched to Dvorak. It was worth it, but it did experience a full month before exceeding my 80+ wpm qwerty speed. (The first couple of weeks would probably have been much easier if I had used a keyboard overlay or use a keyboard labeled as Dvorak instead of qwerty.)<p>Before switching, I wondered how it would affect my ability to use qwerty. Happily, I never lost my ability to be proficient on small keyboards (phone, labelmazer, etc.) that are too small for ten-fingered touch typing. If you switch, you will be able to text away using qwerty without any trouble.<p>But when it comes to touch typing, can you full-on switch back and forth between qwerty and Dvorak without difficulty? I can't really give you a field-tested answer to this question. I make it a point not to touch-type on full-sized qwerty keyboards--I don't want to risk slowing down on Dvorak. However, on the rare occasions when I need to go qwerty on a full-sized keyboard, I get the sense that switching back to qwerty would be fairly easy. When I use a qwerty keyboard I'm a little awkward--I have to think about where the letters are, but I've "still got it". I get the sense that I'd be back in fine qwerty form if I continued on for a few minutes. But . . . why would I want to go back? Dvorak just flows out of your fingers, and now qwerty just seems like something from the Ministry of Silly Typing. Unless you are typing the word "qwerty" over and over again, Dvorak is the way to go.<p>Also, a word on control-key combinations aren't really that big of a deal. But . . . OS X gives you the option of retaining the qwerty layout for control-key combinations if you don't want to go whole-hog.<p>And vim? Well, h/j/k/l still move the cursor the same way, but obviously the actual keys for h/j/k/l will no longer be adjacent to each other. Using these keys to move the cursor won't be as intuitive, but can it be said that vim users are prone to whimpering about things not being idiot-proof?<p>Along the same vein, video/audio editing programs tend to assume a qwerty layout is being used; if the editing app you use allows you to control the playhead with "letters", expect their position to change and be non-adjacent.