Basically dechlorinator is a commodity item. This is why there are a few chemical companies that will make you a dechlorinator. I went down this road, but I couldn't answer my question. "How is aquarium co-op's dechlorinator better?" We could make it more gallons treated per dollar, but at the end of the day, grab nearly any dechlor off the shelf and it's getting the job done.
I feel like this is probably one of those things like proving which paper towel is the best, when reality is, any paper towel basically gets the job done. Sure one might be better suited for a particular job like public bathroom vs kitchen. But if there is a spill on my floor, any are going to work.
In general if any employee is trashing a product, esp something like prime. I question it. I don't like seachem as a company, but at the end of the day prime is pretty good cause the bar is so low, any dechlor is "pretty good"