We are a family of 5-2 adults, 9 year old, twin 2 year olds and ate at 50s and Sci Fi in June
We probably won't bother with 50s again. Our experience at 50s is that the kids didn't really "get" the decor. The 9 year old appreciated it a little bit, but the 2 year olds couldn't care less. Maybe because we had 2 year olds, we had NO schtick from the waitress (another table got it-maybe we just look like we are not a fun family?). I think our 9 year old would have liked it, but it was disappointing to basically get Applebee's service. The food was okay. I had the sampler, everything was tasty, but nothing outstanding. The peanut butter (and jelly) shake just tasted like peanut butter (no jelly) and DH's was icy. I guess the food at 50s must be "Disney Delicious" because if DH could get chicken and a milkshake from Chick-fil-A or chicken and shake from 50s PT, he'd choose Chick-fil-A hands down.
We all love Sci Fi. The food is also basic, but tasty enough if you stick with burgers and shakes. While it was dark, the kids got a glow drink and then LOVED it. They understood sitting in a car and watching silly movies (my child who is afraid of "Where the Wild Things Are" was not afraid of the movie clips). As a family of 5, seating was a little hard...we had 9 year old up front "driving", me with one toddler, DH with one toddler. I would think that as long as the oldest child was 5, then sitting by him/herself as the driver would be cool.