Q: If I switch to Dvorak, will I still be able to type on Qwerty? This is an issue for me since I often need to use other keyboards.
A: Very probably, yes -- if you keep using both regularly. I've heard reports that people who use both will be typing along and suddenly realize they're typing on Qwerty, when they meant to be on Dvorak. Using both is very much like being able to "touch type" on both the telephone and 10-key (computer) keypads -- they're very different layouts.
If you don't keep up practice on both, you'll probably lose your ability to touch-type on Qwerty. That's what happened to me: after reaching over 100 wpm on Dvorak, and abandoning Qwerty completely, I can no longer type on a Qwerty keyboard (such as at a friend's house) without looking.
Q: Is it hard to learn Dvorak? I remember how horrible high school typing class was...!
A: No, Dvorak is much easier to learn to type on. The reason your high school class was so hard is because Qwerty is anti-ergonomic. Remember how long you drilled "exercises" such as typing "f f f ... j j j ... j k l ;"? What was the point of that? This is not something you need to practice -- you don't type stuff like that now, right? The reason you had to type garbage like that is because there are so few real words on Qwerty's home row (where your fingers normally rest). On Dvorak, fully 70 percent of your typing is done on the home row.
Also, you've already learned how to move your fingers around the keyboard to get to the keys you want, so you don't have to learn that part again.
Q: I've heard there are studies that show Dvorak isn't really that much better. Are they true?
A: Hardly. Mostly the various "studies" are the same single, poorly-designed "analysis" being told again and again -- and that "analysis" is based on faulty and biased information. See this page for my formal response to these anti-Dvorak campaigners.
Updated: July 2011