Galvanized to Copper

I'm updating the plumbing in my slab-on-grade home. My inquiries have been met with a wide variety of opinions about how to make the transitions from galvanized to copper pipe. I hear little positive about dielectric unions and some question as to whether there is really any real issue at all. What's the best solution? If you had a connection direction from galvanized to copper in the wall, would you cut the wall open and change it?

Thanks