It made the transition longer and bumpier. I had gained some muscle memory with crtl c etc, but not much. When I swapped to the Ctrl+qwerty+c mod, I got confused and would sometimes hit the qwerty key, but i would sometimes hit the Dvorak key.
Hitting Ctrl q without realising can really add to your workload...
It took me a long time to adapt. Before swapping, I could only type about 2500-3000 characters a day before the pain made thinking optional. Losing half of my productivity at that point actually didn't matter as much as you might think, either way, I wasn't getting much done each day. I was pretty stressed out, and the only thing that stopped me from quitting working with computers was the various encounters with shop staff who would start at a shop one day with a wrist brace, and you'd still see them trapped in that situation a year later.
If I was in a hurry, I would develop 'key panic', and would guess the correct key by trial and error instead of thinking it through first. That didn't help either.
It was totally worth it.