STP fuel system cleaner

what do you have to say about this stuff? does it really do anything or is it pointless... it isn't bad is it? I never used it in my NA but I thought about getting some but thought I'd ask first...

i once used hyper lube fuel injector cleaner and it worked fine. it also cleans your ports.
http://hyperlube.com/
http://www.hyperlube.com/prod_fuel.asp