I haven't tried it, but everyone that I've either talked to or read their posts in reference to it (there is much reference to it over on the ugsupp board) - they all say it is good shit.
you can take half a 100mg tab and it works great, but won't give you an 18hour boner like the pfizer stuff will....
so it sounds like maybe it is underdosed?
He's had a few different batches. I've used the blue ones and the white ones and I would have to say they do contain 100 mg (and yes, I've taken the Pfizers, so I know what it feels like). I've heard the green ones were a little underdosed. I generally use a quarter tab--I get all the benefits with none of the negative sides.