I don't have this problem, just like I don't have a problem with typing both English and Russian on a single keyboard: my brain have learned to switch contexts. I don't use vim-like plugins for anything. :wq
Slightly related: There were a couple days way back that I really wanted to learn to type on a dvorak keyboard (later lost interest). One of my friends was doing the same (he also later lost interest) and gave me the tip that I should figure out which thumb I generally press spacebar with when typing on a qwerty board (my right thumb) and use my opposite thumb when typing dvorak. I found this worked really well, I was able to seemlessly switch between my mostly-incompetent dvorak typing and my good qwerty typing without any mental effort.
While we are on the topic of keyboards and editors, the FingerWorks TouchStream LP [1] keyboard had various modes including QWERTY and Dvorak, as well as Emacs (!) chording.
It's a really cool keyboard. I wish Apple brings it's thumb+index finger twist [2] to do Ctrl-W to their laptop's touchpad. You can see the roots of their pinch to zoom gestures all in the keyboard, and it had much, much more. Apple acquired the company and it's IP in 2005.
[2] Actually, it might have been 4 fingers (minus pinky) twist. It's been a long while. I'm sure I'll remember how to do it once I have the keyboard in front of me. Just like vi keys.
I've heard this in regards to typing speed and it's probably true, though I've never been a fast typist.
As a full time dvorak typist I can tell you that it has definitely helped with my RSI (as has using vi). Dvorak is comfortable. It's hard to explain, but it feels like one's fingers are "rolling" over the home row when typing.
Oh come on, you have all your vowels and other frequent letters right there on the home row. There might have been some issues with the studies that were supposed to show Dvorak's superiority, but if you take a cursory glance at the layout it should be immediately obvious that your fingers will need to travel less because the layout conforms much better to the observed frequencies in most languages.
Vowels and frequent letters? For one I am a programmer, not a writer --my frequent keys are widely different than a typist's.
Second, who said having the all on the home row is better? Studies --nit Dvorak's own-- have shown marginal or no improvement compared to qwerty, ven for typists.
Identifiers in source code are typically base on words, so will share the same distribution of English text to some degree. It should be easy to make a program that takes any text file, and for each character notes how far your fingers would have to move from the home row on a certain layout. This could then quantify the distance on qwerty vs. dvorak. That would provide an interesting empirical verification of this issue.
About the having keys on the home row, I certainly claim it is better, and you should try it for yourself. I will concede that it may not give a speed increase for a seasoned typist, I suspect that at a certain point when everything is in muscle memory it doesn't matter anymore. However, having to move your fingers less is simply less straining, so it will be more comfortable. This was not measured in those studies, so that's why I think they are not relevant.
Since you specifically said “vi users”: The problem is most often – in my experience – that the plugins support only vi functionality, while Vim additions such as text objects are not supported. I love using Vim, but find vi really lacking.
