http://orienteering.org/athlete-of-the- ... navigator/
Emily makes this strange / interesting comment :-
Those that do try mountain bike orienteering often dislike it because they find the navigation too fast and struggle to assess the different route choices quickly.
I say strange because surely those aspects are the best parts of MTBO / Ski-O for an orienteer (but maybe the worst parts for someone coming from a MTB / skiing background). The fast navigation is surely the fun part.