I think one problem I encountered prior to switching to Dvorak was that QWERTY encouraged me to make bad touch typing habits like holding my right hand further toward the top row rather than at the home. This exacerbated my prior inability to pick up ambidextrous use of shift and ctrl.

My error rate is now tiny, backspace is for bad writing rather than bad typing. It is really comfortable to type on Dvorak in all manner of postures. I can type with my hands coming at the keyboard sideways, way above, way below, or while dancing or walking with the keyboard on a moving dolly; I've had no strain issues on any keyboard from doing this sort of thing regularly, or from sustained typing while sitting in crappy office chairs behind desks at the wrong height.

I think it might have something to do with the complete effectiveness of the home row. Because the home row reigns supreme in Dvorak, changes in posture aren't compounded by changes is hand positioning on the keyboard to hit certain motions.