I have dined at Gateway plenty of times. I think the exterior is nice, and the interior is nice as well. Diners typically have a bizzillion things on the menu. I typically have the specials or the main-stream items like burgers or breakfast. There were a few dishes that perhaps shouldn't be experimented with if the chef has never had that authentic food. Example would be ordering sushi at a diner - I'M NOT SAYING GATEWAY OFFERS THIS - it's an example.
The salad bar is good, there is all the veggies you want and there are typically 2 soups. I usually have the salad bar, Anyway - it's clean, always friendly and reasonably priced.