As a rule, Iíll go for sci-fi over fantasy when it comes to movies, but fantasy over sci-fi when it comes to books. Fantasy is done right so rarely in movies that I always feel like watching a fantasy is a gamble. It will either be really good, or it will be a waste of time. Sci-fi is just a better bet when it comes to movies.
I prefer fantasy as a genre but there aren't as many fantasy movies I have enjoyed. The Lord of the Rings and Hobbit movies worked well as films, as did the Harry Potter series, but most of the fantasy books I like haven't been adapted into films.