I use Dvorak, and I have almost no problems typing QWERTY. But this only came after I became completely fluent in Dvorak. When I still had to think to type Dvorak, I couldn't switch to thinking about QWERTY without getting all confused. Now I just peek a little at the keyboard with QWERTY, especially for non-alphanumeric symbols, but it's no problem.
I had to abandon Dvorak because it killed my ability to do QWERTY. It was also an almost traumatic experience because when I was going through it I felt like I was going crazy or that I was just plain stupid. How could my brain possibly discard 20+ years of QWERTY after just a few weeks of Dvorak.
But having said that I recently learned that other people have had the same experience and so now I don't feel so bad and I want to change again.
Same story here. There was a time during my transition to Dvorak where I kept tripping myself up if I tried to type QWERTY, but once the Dvorak layout went into muscle memory QWERTY came right back without any special effort on my part. I still have to peek, but I had to peek before I learned Dvorak too (that's why I switched to Dvorak).
