Well yeah, cheaper 'stainless' systems like these get a bad press by many.
If one lasted me say 2-3 years then I'd be happy with that, especially as they can often be less than half the price of the stupidly priced Millteks, which ALSO seem to be getting some bad reviews recently (on fit/build quality etc).
I'd rather buy a cheap one that made the power and had a pretty tailpipe than a reeeeeally expensive one that gave me problems aswell,.........that would seeeeeriously get up my nose.
Also, would I still have the car in 3 or more years time?.......probably not.
I've had Powerflow on three totally different cars now without any problem what so ever (and made good power too). On the flipside I've also had Magnex and Scorpion etc, and had a right old faff of a time with warranty clams when components have failed.