In my opinion, GPLC is the BEST no product on the market, hands down!!! The BEST brand I've found is mhp NO BOMB. It has GPLC and a couple other ingredients to potentiate the effects even more.
As far as arginine based no supps, it's smart to AVOID THEM, AT ALL COSTS!! Arginine, in large amts(as used in most no supps) can and does cause pancreatitis!(I have a good friend that just had to have surgery on pancreas, and is permanently damaged! That person can't ever eat a high protein diet again, and has to be very selective in what is eaten, as it causes SEVERE pain as well as elevating pancreatic enzymes)... Arginine is actually used in medical research to CAUSE pancreatitis(in rats), in order to study it... Look on the labels, there are many forms, and they aren't always spelled out(aakg, l-arginine, akg, etc, etc)...
I know of one preworkout no drink that has reformulated their product to contain no arginine(superpump max), and NO BOMB is arginine free... Nearly all the others contain it to some degree... Check labels guys, it's not worth destroying one of your most vital organs, to good health!