First there is something just inately wrong with letting "Some guy at GNC talk you into buying anything" Buyer beware. The majority of sales people there have no training beyond a sales tape they listen to on a walkman as it guides them through the store explaining the GNC way of selling! Second certain Items have PMs attached. IE Promotional Money which is like a commission if they sale that particular product.
Second NO supplements have been around far befor the big publicty campaign to push them back then they were simply called what their main ingrediant is (Arginine). Argine supplements usually the AKG variety but befor the NO boom they were cheaper.
A few observations NO does cause peripheral hemodilation or opening of the blood vessels which causes a better pump or at least a quicker pump so the illusion of size is in place. And last but not least if Arginine supplements caused such massive size gains why wasn't there a buzz about them before NO hit the shelves? Oh I forgot because the first buzz was that Arginine supplemnts caused massive GH release (Not at the degraded doses that you could get from a few pills anyway)!
None of this was meant to be a slam against the person who started this thread but none the less supplements can be exspensive research befor letting a underpaid salesman on the hunt for the elusive PM talk you out of money that could be better spent.