As a supplier, Cobb's does the job. Product, packing, shipping, pricing, etc are all ok. The customer service protocol is lacking, but resembles most of the other suppliers I've dealt with, but don't enjoy.
The phone staff (I've dealt with) are of the same caliber as I would expect if I was speaking with the mechanic from the back, and they seem to have "salesman" personalities rather than "customer service" personalities.
I don't like to shop at places where whatever "salesman" I dealt with the first time adopts me as his own personal customer and is angry and offended that I purchased another product from whoever was available when I called for future orders. The car lot sales approach (salesman free for all) doesn't promote future business, but actually drives it away by adding drama or complications to the purchase.
My local janitorial supplier has a dedicated saleman system, BUT I can buy from anyone at their location and it is credited to my salesman. This way their employee's aren't mad at the customer for making a purchase from their own business.