I learned vi after switching to Dvorak - so I don't have any vi-Qwerty muscle memory. That makes for a painful 5 minutes at someone else's desk, but they pick up vim commands better if I tell them what to do.

I echo the RSI sentiments though. Dvorak is more comfortable for myself. I'm somewhat tempted to try Programmer's Dvorak for the brackets/braces/parens at some point, but I do like having my (Dvorak) TypeMatrix 2030 keyboard reflect my actual keymap.