If they are the cheapest seeds around do you even need to ask about the quality ? I've personally never heard anythign good about their seeds and have heard a few bad things. I would stay away but that's just me.
Most just figure the price is right so the people saying not to don't know what they are tlaking about or you just hope you get lucky. The story turns out the same, you end up with crappy plants and a lot of wasted time.
I usually tell people to stick with serious seeds, they are moderately priced, all their strains are super great, they grow well, and you won't have too many strains to choose from issues.