MA Research sells it.
Like with most PDE-5 inhibitors, not everyone responds to same to all compounds. For some people this compound works great. For others it works only moderately well...and for some others, it doesn't work at all.
It doesn't matter what anyone else's experiences were with it. Only personal experience can tell you how YOU will respond. Look at tadalafil (Cialis). Tons of people LOVE it, yet I don't respond to it at all...not AT ALL, regardless of the dose. It's the exact same way with the other PDE-5 inhibitors. Personal experience is your ONLY teacher.