I switched a long time ago from qwertz to de-ergo, I did not know dvorak at the time, but it was a very profound and interesting experience to see the wiring in the brain to change. After some years I changed from de-ergo to NEO[1] and I am still using it and will probably never look back. Having most of the important programming characters (\/{}*?()-:@) on the home row is the best thing that ever happened to me.
This is of course limited to the German language.