As has been said numerous times, it has both positive & negative effects, and it doesn't necessarily affect everyone the same. Unfortunately, it's not black and white. Still, like I said before, it shouldn't be treated the same as 'roids. Nor should it be OK to fight "under any influence".
I think, and go ahead and correct me if I'm wrong, that it's pretty much proven to inhibit reaction time universally. I know it can help people train because it helps reduce pain but I think the reduction in pain is going to be overridden by the reduced reaction time. Plus, in a fight adrenaline takes over and you don't feel much pain anyways. I just don't see how it's going to help in a fight and I smoke weed all the time.