What more can be said? It stains clothing, I can confirm that.
I didn't see many negatives out there on this stuff, the most holy of topics is where to apply it (fitting face, back or threads). Knowing that liquid on threads will mess with the torque values, and besides, if gas is leaking out there, you have another issue and this stuff ain't the solution....
So I opted to apply it to the face and back of the flare, to allow some lubrication for movement while applying the torque. And what do I know.... no leaks.
Although the price of this stuff is high, and I cannot really confirm it did anything positive, I don't believe it caused any negative (other than staining my shirt, but that's my fault).
Assuming it did something positive, and I have enough quantity to do all the eastern seaboard HVACs, I cannot complain. And if it did help (as most people out there claims it does), at this price I cannot complain because if it saved me from just one leak, it's paid for itself several times over.