I tried dvorak and even colmak; for a while a friend and I decided to convert; but while I think they're more logically laid out than qwerty, thing is, I also read all these reports that said that the fastest colmak/dvorak typer isnt significantly faster than the fastest qwerty typer. So then the only argument for switching was RSI related arguments - but then I've never suffered RSI from qwerty. So the two reasons to switch, eventually fizzled away, for me anyway. Even tho i do think other layouts make more sense, in practical terms, I no longer felt the need to switch.
One of the lessons i drew from that is about just how adaptable human beings are, that even given an illogical and probably inefficient layout like qwerty, our bodies and minds adapt enough to it that at a practical or functional level, once we've learned it, we do pretty much just fine.
Its not unlike with languages I think. Some language grammars are very illogical, make little sense, are inefficient. But once you grew up learning and using it, then you can make it do what you need, and the learning curve to another 'more efficient' language is much greater than any efficiencies you might ultimately obtain.
Ie, it might make sense in terms of logic, but maybe not in terms of cost/benefit.
I guess which goes back to my argument about sticking with IE, too, lol.