I have and use both D21 car wash and D22 wash and wax. D22 wash and wax is one of my favorites. I like D21 for really dirty cars as D21 is a strong wash and I would not use it as everyday or maintenance wash.
What do you want to know about the detailer line washes?
As to being better than GC and NXT, all depends on what you are looking for in car wash. Both GC and NXT are good car washes and are available almost everywhere.
Eric