Hi Angela,
You have asked about two very unique dining experiences at Walt Disney World and my family has enjoyed meals at both locations on more than one occasion. While I love both, if I had to choose between the two, I would pick
50's Prime Time Cafe. Between the servers' unique roles as "aunt", "cousin", or "uncle" (to name a few), and the multiple dining areas, each with its own twist on the American kitchen of that time period, your experience could be completely different each time you dine there. On the other hand, the
Sci-Fi Dine-In Theater is truly a one of a kind concept. My kids love dining in the old-fashioned cars and watching the black and white film clips from years gone by. However, the film is on a loop and it is the same one I've seen multiple times. So, while it is equally as entertaining for different reasons, we prefer 50s Prime Time Cafe.
But, to answer your questions regarding the seating at Sci-Fi, many of the cars have three rows that can easily fit two adults. However, as a family of five, we have gone and only taken up two rows because the kids could all sit in a row together. So, depending on the ages of your party, it could be possible, but I cannot guarantee that you could sit seven together. There are a limited number of small circular picnic tables at the back of the restaurant along the wall. However, to my recollection, they seemed to hold only 2-3 people.
Have a magical day at Disney's Hollywood Studios!
~Allison L