Atmosphere: kind of neat, retro drive in theme. The movie repeats movie and commercial clips from the 50s. You sit in "cars" with two people in front seat, two in back, so you are not facing your dining companions. And if you are a table for 2, you will possibly be sat with another group.
Food: limited menu with basic burgers, salad, sandwich. Shakes and stuff. Yes it is expensive for what it is but that's WDW. Agree with sticking to a burger or chicken sandwich (things hard to mess up), and you should be safe.