I wouldn't say alternation is always better -- in many cases, having successive keys close together is just as good if not better - "There" the first three letters "The" are typed with alternate hands, then the next three - "ere" are also easy to type fast because they're to each other.

I haven't used a dvorak keyboard, but the next to each other keys are really a part of my flow. I really don't know how "<esc>:wq", "<ctrl>a" and so on which are part of programming work would translate to dvorak.