I'm convinced that none of the reviewers use prosumer type cameras to take their personal photos. The ability to hold the pre-focus when something moves to take advantage of the fast shutter release is important. Especially if you are shooting kids or people at an outing. They never test the continuous focus mode.
My Oly doesn't have continuous focus and I assumed it worked like my D7I and FZ10. You can hold a pre-focus and they continue to adjust the focus. The FZ10 manual says the mode is primarily for pre-focus.
I'm disappointed the Oly doesn't work that way. They call it "fulltime AF" and it is different from "continuous AF". I just downloaded the reference manual for the 770 and it indeed works like you say. I have to correct another post where I gave some bad advice based on a poor assumption.