I'm not sure about the virtues of paying the stiff startup fee of learning Dvorak if all you know is QWERTY, but if you have already paid I certainly wouldn't suggest losing it. And I'm very, very tempted to ensure that my kids, who are all too young to be typing at all, simply start on Dvorak. If you're starting from scratch entirely the choice is pretty clear to me.
The thing about shortcut scrambling is oversold; I think it sources from people theorizing about what the problems might be if they switched, not people talking about their experiences. In my actual experience, relearning the keyboard shortcuts was a negligible part of the experience.
Such as ctrl+z, ctrl+c, ctrl+v, ctrl+w, ctrl+t, ctrl+n, ctrl+s that requires two hands on dvorak ("especially" on an ergonomic keyboard) - or at least requires the right hand (=> you can't use the mouse) or you have to reposition the left hand (not acceptable).
This is not something that you can just relearn and this is something that seriously hinders at least my workflow.
The reason for why I've not tried this is probably mainly because it would scramble all keyboard shortcuts. Shortcuts are designed for qwerty (a shortcut that you can't perform with your left hand anymore is a huge loss) and many combinations are a huge part of the workflow of many applications. I found this to be a complete showstopper.
I think there are ways to automatically switch to qwerty when ctrl/shift/alt was pressed and maybe I didn't research it enough but it felt like a cludge and I wan't something that is platform independent and easy to enable on any machine.