Love the paint, but given speedpaint 2.0, I'm not sure I'll buy anymore. Not unless citadel drops the price.
I've been using Magos Purple over a bone undercoat and getting great results on the tentacles and other nasty bits on Plague Marines. On a light undercoat, it comes out pinkish with purple in the recesses. As far as contrast paint opacity goes, this paint is more towards the shade/wash side of the spectrum