i love them. most of the time ill use a n.o product with beta alanine for about a month or two (Assault, c4extreme, currently trying no xplode 2.0), before switching to a n.o product without it (always go with no370). I never seem to get used to the pumps, but the beta alanine tingles are something i really like that i try to cycle off of so it never feels old.
I was given lots of samples by a friend at gnc to try, and im currently trying a new product called nanostim which im stacking with n.o explode. we'll see how this goes and if it even makes that much of a difference