I used to buy generic mac -n- cheese, until the brand name became cheaper than the no name brands. *giggles* I just find that funny.
I tend to buy things based on quality and taste... instead of name brand. I really couldn't tell you.
Of course there are some things that have to be name brand, but then there are some things that have to be generic. Cereal... most of which I buy generic, because the flavor is a lot better, and it is still a little cheaper.