I do hear this a lot, and I have no comprehensive experience with Dvorak, but as far as I know there is no real support for the premise that Dvorak makes you type faster, at least. I'll buy that your fingers might not tire as easily.
"This was a humongous waste of time. The program to do the analysis is about 700 lines of code, and went though about 3 iterations. I am most disappointed by the lack of benefit offered by a more efficient layout; even when considering a purely optimized layout you only get 21% savings over Qwerty."
Of course, there are other ways we could change keyboards. For example, accepting even more data from your digits could be a useful avenue to explore. 20% improvements are not that spectacular, maybe there's a contraption that is conceptually like a keyboard but is 10x faster (so 12 cps -> 120 cps?).
Alternatively, plover. but then custom dictionaries and bleh..
