I currently use a qwerty layout and I wanted to try the dvorak one. My main concern is about still being able to retain the qwerty speed. I know this has to do with muscle memory, but I'd like to know from former qwerty users whether they still retain good speed on the qwerty layout after switching over to dvorak. Also, has anyone tried to switch back to qwerty from dvorak ? How much time does it take to regain the old speed. Currently I average around 75 wpm on the qwerty format.
I would say in about a month after you first tried it, you'll regain your former speed (and if you use it to program, you'll most probably increase it. Especially if you type with more than two fingers).
In my experience, changing keyboard layouts is traumatic, but doesn't leave scars. What I seem to witness is that during the early days the change is quiet significant and we experience a dramatic drop in typing speed. This makes us believe it was a bad decision and many tend to go back. But if you persist, you'll start witnessing improvements right during the first week and soon enough your muscles will be trained.
What's more, 8 months after I changed to dvorak, I switch back and forth between my laptop traditional qwerty layout and my external dvorak keyboard at ease. You can certainly do it yourself since your current typing speed is faster than mine, which indicates you are more skilled.