We just booked our next trip and the ONLY place my 13 DD wants reservations for is Sci Fi. The atmosphere is unique and the food is great. I would choose Sci Fi over the Fantasmic package because no matter where we have sat at the show, the seats are fine. You will see the entire show no matter where you are. Also, we prefer to sit higher up as it is a nightmare laving the show - and the closer you sit to the front, the more likely you are to get wet, and it is not exactly refreshing... The restaurants that are included with the Fantasmic package are nothing to blog home about. Italian food shouldn't even be eaten south of NJ...
Also, Sci Fi doesn't show a full movie, just clips of movies, short cartoons, commercials. They are appropriate for all ages. Most likely, you will see the same clips again depending on how much time you spend sitting there. My DD enjoys the familiarity of the same clips coming up again.