Is anyone here proficient on both QWERTY and Dvorak?

I mean are you able to type at a reasonable speed on both and switch layouts when required? If so, are there any exercises that help with keeping both layouts in your head? I make a lot of mistakes when typing on QWERTY because of awkward finger movements. I'm currently learning Dvorak, and can type reasonably well right now, but I have to think a lot while typing.