I have some of that but have not used it to chamber with yet, but it is definitely thicker than the viper's venom.RE: Tap Magic Xtra Thick
There's a lot of factors which make it difficult to generalize, the speed, hss vs carbide, amount of feed, machine calibration, tooling, etc...
That said, for the amount of cutting fluid used, and the cost of viper's venom, it seems like a no-brainer to keep a small bottle on hand. I like that old school dark cutting oil with HSS, but tend to like thinner with carbide. All of our mileage varies...