We "jumped ship" on RCI world cruise in LA a few months ago (did first quarter, 63 nights). We already have Viking B2B booked for 45 days (down under) beginning of next year. The Serenade world cruise did not do a full circumnavigation of Australia (which Viking does). Plus we had no interest in going through the Suez Canal or into the middle east. (that was before they were forced to cancel that route).
We are rejoining for the last quarter (62 nights) in Barcelona doing western Med, Baltics, Greenland, Iceland and then working our way down eastern US seaboard back to Miami.