When looking for a place to eat in Saigon, there are two options. One is the street stalls where locals eat. They may look somewhat dirty, but it is in these streets restaurants where I found the best food in Vietnam. Most of the times you sit in a small plastic chair in the street. Each of this restaurants is specialized in one type of food (noodles, soups, beef). As in the rest of Vietnam, things go really fast in these restaurants. You wait for a free seat, order your meal, eat, pay and leave. The whole process may take less than 15 minutes. You will also find these food stalls in all local markets.
For the ones looking for a restaurant to eat more properly, you will find plenty of options in Saigon. In the picture you see one of my favorite restaurants. I do not remember its name. It was not far from the reunification Palace, in District 1. No matter what I ordered, it tasted really great.