I believe you are all correct, depending on the circumstances. In relatively flat highway driving, I vote for cruise control to win the MPG contest. Conversly, in all other driving situations, especially in hilly country, cruise control usage will lose the battle to a good hypermiler driver, practicing Driving With Load (DWL) and more coasting time. Cruise control will attempt to maintain speed going up the hill(s), at a tremendous MPG penalty. Also, the cruise control must be disengaged to coast. DWL techinique entail loosing a little speed going up hills while maintaining a relatively constant RPM. Doing this will beat the pants off Cruise control. Your instataneous MPG reading tells the story here.

Use of cruise control in Florida with a lot of flat land, probably makes cruise control quite effective most of the time. So IMHO, cruise can win at times, and lose at others. And if the driver is not concentrating on FE while driving, cruise is probably a better option.

Great hypermilers probably don't remember where the cruise control is located