[rgoulter]

I went from ~110 pb, 100 average (on common word typing tests) on row-staggered QWERTY with an untrained hunt-and-peck to ~105 pb, 100 average (on common word typing tests) with Dvorak layout on an ortholinear keyboard.

I'd already spent the time to learn Dvorak layout on row-staggered keyboards. Having had that training, picking up an ortho was straightforward. (Although my average wpm on typing tests after picking up the board would've been ~90).

I suspect if all your fingers 'know' is where the keys are (rather than following discipline of 'column per finger'), then adjusting to ortholinear would be harder.