I bought the head version of this amp for my brother for his birthday. It's now on my list too. A couple of things off the top of my head:
-It seems to get its versatility from what you're plugging into it. Obviously, there aren't a ton of tonal controls on the amp, it's extremely straight forward... but if you hit it with hot pickups, it breaks up nicely. If you dime it, it's a beautiful distortion... and on a 4x12 cab, you can be in the same room with it and it won't tear your head off, but the neighbors won't like you if you play it at home in the middle of the night.
Put a hollowbody or a tele into it, and you can pull out some sweet blues tones. Roll back the volume and it gets really jazzy, put a big muff or rat or something in front of it and it will slam.
It's no thd or anything, not exactly boutique... but it's probably the best piece of gear you can get for $100.