All my sailboats had a single lever control. I was a bit concerned going to a dual lever with the current boat. I found I got used to it very quickly. Not sure I have a preference at this point.
If I was to make a change, I would be more concerned about reliability and ease of maintenance. Electronic controls would be great as would something that would be easy to add a remote control unit to in the future. Given all that, I wouldn't care about single vs dual controls.