Oh yes, I own one and it is amazing. The crunch and lead channels are superb. And yes, it can growl. I have the X100m classic which is sort of British flavored, and it can growl. listen to the demo when he gets up to the gain channels.
You can find the X100's used in Italy for a lot less than 4k. New they are expensive, same with the Mzero, but I found sites in Italy and they ranged in price from around 1800 to 2500 used for x100's. I have only seen a couple used Mzero's used.