A decision to go to one chain restaurant over another is usually a question of proximity and immediate needs. I need a donut now. There is a Krispy Kreme within walking distance, or I can drive to Dunkin' Donuts. The last thing I'm going to do is to spend another 10 minutes to log on to Epinions to decide. Chain restaurants are like Stepford wives.
Chain restaurants are franchises.
This puts a low ceiling on the quality of the food you're going to get. Service is minimal, usually of the assembly-line variety, and also formulaic. Even restaurants with table service don't require too much of their servers. More importantly, they tend to hire kids who are just out of school, at minimum wage. These kids don't always have a lot of experience in the food service industry, and it shows.