As a former heroin addict who used to buy from these guys, this article is spot on. They were always polite, fair and non-threatening. They were usually (relatively) on time. They really did have a great customer experience relative to the alternatives (which I also used from time to time). The thing about them keeping business hours is also accurate and was amusing to me at the time, except of course when I ran afoul of the deadline.
As I recall, they even engaged in some network marketing. The group I bought from had a standing offer of a free balloon in exchange for bringing them a new customer.