I would say that it is much more efficient. Not that I ever had repetitive motion injuries from typing, but you definitely don't need to move your hands as much on a dvorak board. I also find the layout to be much faster, my WPM's are higher now than they ever were on a QWERTY board. If you google the Dvorak layout, you'll see that QWERTY was reverse engineered to slow down typists and Dvorak was engineered to make typing faster.
As for having to use a QWERTY board, yes, that can be annoying. I can no longer touch type on a QWERTY board, but I do think that I could re-learn and maintain my abilities on both if I wanted to (I've read that it's not all that hard to do both). I'm pretty sure the only reason I can't do both is that I completely dropped QWERTY. This is really an issue when the computer you're going to be using is not one that you regularly use.
If you have a computer you use regularly, such as "your" work computer, you can set it up in Dvorak. (The specifics vary by operating system, but in Windows you do this through the language bar.) Pretty much what this option does is software re-map your keyboard. So, you would press "qwerty" on your board, and the computer would receive "qwerty", but the computer would switch that to "',.pyf". (I know I didn't use the " correctly, but that was to avoid confusion). That was actually what I used to do in my desktop computers, and that is still what I do on my laptop. (On my laptop, a Dell Inspiron 6000, I've actually popped off the key caps. I had no use for them since they were QWERTY, it looks very cool without them, and it's silent while typing. Having smaller keys also made me a more accurate typer, though it causes some issues when switching back and forth with my TypeMatrix, which I will describe below).
Once I decided I wanted to stick with Dvorak (I tried and failed a few times because I got frustrated), I set out looking for a keyboard that could do hardware Dvorak (meaning the keyboard has a different physical arrangement and the computer, on "normal" settings, would not have to reinterpret anything). I ended up with a TypeMatrix 2020 keyboard (Product Overview of the TypeMatrix keyboard), which can do hardware Dvorak and hardware QWERTY. It also has a different layout and scissor keys (laptop style) that I've come to love.
Sorry, that's a bit of a long answer.