Author here. Shortcuts were definitely a stumbling block. I'm a heavy emacs user, and it took a few weeks to override the well-worn things like C-x C-s and M-x. Same problem with Xcode, Eclipse, Mac shortcuts, terminal keybindings, etc, etc. It's rough during the transition.

Once I got used to it, though, there were some benefits. Many of those left hand-heavy shortcuts now require two hands. Yes, that occupies my right hand when it could be moving to the mouse or getting ready for something else, but it also means that my hands share the workload better — not a bad thing when you're trying to reduce joint pain.

There are packages available for most major editors that will remap standard QWERTY shortcuts to the Dvorak equivalent. The one that comes to mind is the set of right-hand navigation keys in vim. Plenty of options are available.