This came up last year. See
this topic, and in there you will see links to two previous discussions of
compere. It is indeed a word little used in America, hence classed as rare.
The upshot then was to leave
emcee as a common word, but I obviously wasn't totally convinced, as I said, "I'm leaving
emcee as a common word for the time being." I'm happy to reconsider it in due course, but I think Les's point is well taken - despite my in-depth consideration of this question on previous occasions, I didn't spot
emcee yesterday.