Pretty heavy sounding. I tried a bunch of them when i met James at the toronto amp fest. We tried the chimera, gryphon, and the polaris preamps, which he ran into a 50watt EL34 poweramp thinger... kinda like those egnater module style, but in a big purple peters headbox.
Polaris was on the gain level of classic rock, but if you dug into your strings you could definately get some heavy tones out of it; not real chug chug, but you probably know what i mean. Very versatile, very responsive.
The gryphon was what we played most, and had oodles of gain. It also cleaned up quite nicely when you backed off the guitar volume. Went from clean to classic rock to chugging metal. Very tight response. The soundclips on the website are very true to the amp.
The chimera was... overkill hahahhaha. It hadd more gain than i'd ever need. Its just like the gryphon, but more gain. Definately coudl slay. We didnt spend much time with it, but from what i did hear, it was basically a gryphon where the gain knob started at 5, and went up to 20. It still cleaned up pretty decently, but not as well as the gryphon. Perfect for anything brutal. With the tight response, it could probably djent, and now that i think about it, i wish we tried it out hahaha.
In high gain situations, both the gryphon and chimera were Very tight and heavy sounding, i want to say almost like a vht, but nowhere near as sterile and dry. (there was a vht UL at the ampfest). The high end was blistering, but not ear piercing, nor was it fizzy at all, it was pretty sweet. Again, the soundclips are very true to the amps.
Since then, it looks like hes modified the polaris and gryphon, but i bet they just sound even more badass now. I'd recommend you give him a call, he'd probably be happy to answer any questions. Real stand up guy, helped me figure out some stuff for my home projects :)
