Not used it in anger properly live but I have Had a lot more time with it through headphones and my enabler.
The limiter comp pleads to work well and doesn't kill dynamics. The only negative is as there is no indication (LED/s) you don't know when it kicks in so you are setting it up blind so to say. The input sensitivity seems key in getting the signal level right to allow the comp to work properly.
The amp generator is very good. Tons on low end available and the EQ is simple but effective. It dies a good job of emulating a tube amp and the breakup up is very natural. I copped a lot of tones including trebly OD, fat OD, grindy and hairy! I wouldn't say that with the gain turned right down it was über sparkly clean but then it is modelled after a B15 and other tube amp. I'd be happy to use it as my amp sound or as my OD sound.
Now, finally we come to the Gamma Fuzz. This is a very interesting beast which I initially disliked BUT now I get it. I like muff fuzzes and having just ditched a Wren & Cuff Box of War for a Tall Font Russian this trend continues for me. The gamma is not a muff fuzz but what it is is a great synthy one IMO. The in knob is very interactive and simple, maxed its a wall of fuzz sound and with the amp generator kicked in can get muffy. As the knob gets turned down it's gets deeper and darker, less distinct but not in a bad way. On low settings I think I could use it as a dirty boost.
In summary I'm pleased with my purchase. I have a Cali76TX as my top end comp but it's huge and the ABS contains what I think is a minimum for me to make noise. I never play without out a comp and I get that and an OD (this is how I would use amp generator probably) and a fuzz so I can grab it and take my sounds with me. It's not cheap but it is cool and useable. Mates with my JDI I'd wager this would be ago is studio tool too.