the product.
That said, there are huge differences in ease of application, and certain products in certain product lines are easier, last longer, and result more consistently in "glass like smoothness and shine and beading" than others.
I know the Petersen likes Griot; other's like Mother's.
I wonder how much of the brand loyalty is like most other product categories - a bit of fan-boyism, and how much is really differences in the results.
Washing and waxing by oneself does result in a closer connection with one's vehicle. At the very least you know the true condition of the vehicle and where the scratches / dings are.
Cheers,
TM