Well, April 21'st has come and gone, and the algorithm update Google promised to promote mobile-friendly designs on mobile searches has been a bit of a "bust". To be honest, we've noticed very little changes in mobile search, and in fact, some mobile searches are still dominated by sites that are not mobile-friendly.
Now - Google mentioned that all things being equal, a mobile-friendly site should have a position advantage over non-mobile-friendly sites. Well, the searches I performed did not show that effect. In fact, searches for accountants in our local area show a lot of older sites still ranking above some responsive sites. Go figure!
I'll revisit this early in June to see if that is still the case.