I do use it. It makes a lot more sense if you use something like LISP or Clojure because (parens are king).
I really enjoy programmer dvorak. As you say, re-training copy and paste is a bit of a task, but my hands feel far less fatigued typing on dvorak than on Qwerty. Now I am type-fluent in both due to necessity and public terminals, but prefer to use programmer dvorak. I really like the numerical layout because there is some rhyme and reason: Left hand from middle out: 91357%, right hand from middle out: 02468` ... so it's a lot easier to type numbers because of that break-up. I don't mind having to hit shift for numbers because it makes for faster coding.
@ &[{}(=*)+]!# @ %7531902468`
Top row without and with Shift