For my DW and I, Sci-Fi was a one or two-time place. It was fun the first time because of the setting. The 2nd time -- well, we realized that the food was, at best, mediocre, but quite filling. The movies had not changed over time -- same scenes, same trailers. So that was a little boring.
As Jim said, lighting is minimal, so dining is quite an adventure. (Is that your sandwich or my fries?)
Having said that, the shakes were great and the desserts were good. We go now for a snack or dessert -- unless we are too full. We avoid it for a full meal.
But I would recommend it for a fun, first-time, one-time visit.