Funnily enough i do know what you mean and its a big difference, also when people tell you there giving you strains like purple haze be wary there probably talking shit. I know this guy in rutherglen hadn't smoked any green in a year but said he had smoked white widow and shit. He was talking a big pile of steaming shite. All he had touched in a year was fivers bits of hash :|

The dealer i use these days is a good mate so i don't get any problems usually, as for known strains he doesn't usually know what the fuck it is but its always good weed.