We had a back seat and it was fine (usually a party of 2 goes in the back seat, party of 4 in the front and middle seats). The cars are angled in such a way that you can see the screen easily between the people in front of you. Our car had 2 kids in the front seat, parents in the middle, us in the back.
It was a really fun atmosphere and the food was decent, maybe at a TGIFriday's level. There's a review in my September dining report.
I'm not dying to go back anytime soon, but I'm really glad I did it once (and I'd be happy to go back someday, I just mean that with all the possible restaurants out there, there are others I'd try rather than repeating Sci-Fi soon).