I've read that as well Steve...
I can't tell you what range to avoid, but I can tell you that I've had Riff Raffs and MQs in my (Epiphone) mahogany SG, and that they both work nicely.
I was considering Warpigs for a while, and would have regarded them as a safe bet, but as you can see from my sig, I'm a more of a "vintage" kinda guy on the humbucking front!