I happen to live within sight of the Ozark's branch of this "cafe". The place is more of an annoyance than anything. I attend school with three quarters of the staff, and have had the unfortunate experience of eating there on several occasions.
First off, if you want to eat at Lamberts, arrive an hour early and dress appropriately, because you'll be waiting outdoors until they find you a seat. Also, do not expect a cozy little atmospere for a quiet dinner with your family or a date. The place is chaos. Some employee is always yelling out asking if anyone wants some complementary sidedish, or rolls are being thrown, or some tourist's child won't shut up.
Understand, this place is a tourist trap. There are usually one or two tour busses in front of the place at all times. The food, although plentiful (all you can eat, but not buffet), is nothing special. Their main goal is to filter people through as quickly as possible. But do be nice to the employees, they don't like it there, it's just Lamberts is the biggest employer of teens in the area.
Also, if it's your birthday while you are visiting, show them your liscence as proof and your meal is free.