With respect, the problem here is like any illegal or controversal item. Those that are opposed and those that are not will both exagerate claim in their own favour.
The best that you can say is to repeat what Kat said.
Or offer them a gun with one chamber empty and ask if they feel lucky.
The problem with these sources is they may sell you sugar, they may sell you stuff that is damaged or out of date. They may sell you good stuff. But ask yourself, where did the good stuff come from?