[silentbicycle]

I use Dvorak, and have for about two and a half years. At this point, the benefits seem sufficiently obvious that I wouldn't go back to Qwerty. It took me maybe two or three weeks to get reasonably proficient with it, and after a month or so it was a non-issue. (It's a completely different matter if your primary keyboard layout is German or something, though.)

FWIW, I use Emacs (heavily), and Dvorak works quite well with it -- all the C-x C-v C-c C-s etc. stuff isn't all clustered on the left hand, which is usually also the hand pressing Control.

Also, as a data point: I don't have any problem switching between Qwerty and Dvorak as necessary, though now the former feels like a parody of a good keyboard layout. (Seriously. Semicolon, home row. J, home row. Why?)