From what I'm lead to believe Benzalkonium chloride is not as good and is indeed a lot cheaper to produce and buy.
Didecyldimethylammonium chloride is what's in benz biocide and algoclear pro the other two brands I've used. They also don't hide the fact what the actual active ingredient is unlike some.
I still can't believe that someone can bring a new product to the market and produce an msds and we still have no idea what the product active ingredient is so we can get a true comparison if it's good value or not.