Had one for a while, ultimately it didn't have the bite or edge I was looking for. Kind of a dark amp, albeit massive sounding. I have heard people call the Fortin sound "dry", i felt it lacked a sizzle that I was looking for. I liked the cleans a lot, but the shared EQ was also a real pain. Could never get the channels to balance properly.
I've had an RD20 and a Thrasher. I sold the RD20 and returned the Thrasher. In hindsight I really SHOULD have kept the Thrasher around as I got some great tones out of it. The RD20 was pretty cool as well but I found the gain channel a bit noisy. (disclaimer I live near radio towers and have terrible trouble with RF noise here)
I may end up getting another Thrasher or bringing home a 667 eventually. I'm also very curious to see what shows up at winter NAMM as I know they're working on amps for George Lynch and Nuno Bettencourt which will probably be right up my alley.
I think you don't hear much about them here because they're not boutique and are basically marketed as metal amps. I also think the markup on them is a bit ridiculous for Chinese manufactured amps. To give you an idea I was able to get a price match of $1309 out the door on the Thrasher I had. A lot of Fortin's fans were also the rah rah 'Merica types that threw a fit about the amps being built in China (which is funny as hell to me given Fortin is Canadian).