It seems most all chain shops are like this. From what I have seen it comes down to each location's employees, their knowledge and ethics concerning fish.
The problem I often see is that they will have a good fish section at a location, for a while. Being a lower paid position, and the better employee in regards to aquatic care usually being the sort that is looking for a better position, finds a new job. Their replacement may, or may not be as adept in aquatic care, so things may change for the worse in a relatively short amount of time.
The flip side is that the opposite can happen, and a location that has been a poor choice for fish can shape up pretty quickly with an employee that looks at their job as more than a paycheck.