I seem to average 5 mpg less with using cruise control than without. Main issue is that going up hill the rpm goes much higher with the cruise than when I simply adjust with my own foot pressure.

Still trying to get over 50 mpg (at the pump) though. I don't know how people get it up into the 60's. About 10k miles so far.

My highest "average mileage" has been 76 mpg, and the worst around 35 mpg for short distances.

Bob