JV, it is the preferred method to install real boxes in the wall, and fish wires to the boxes.
Moving furniture around is a non-issue, as these sets require a fairly substantial mount on the wall.
Generally, I place the receptacles behind the set, down low (so you can easily reach them) and off to one side (so the set doesn't block access. Power on the left, cable on the right. The poser gets a real, all steel 'cut in" box, while it's ok to use a "ring" for the cable. I happen to like the Panduit plates.
