I have a 2012 QR and its killer amp. I have a Splawn straight cab with Splawn Small Blocks that is the best cabinet I've ever owned. I don't have the amp in front of me but my treble/bass/mids are all set between 4-6 and vary. I stick with 2nd gear mostly, but sometimes go to 1st on gigs. Gain is usually around 5.5 to 6.5, and I have a Tube Screamer that I kick on once in a while. As far as using the effects loop as a volume, I didn't see that much of a difference in the tone and I'm happy without the loop.
The clean channel is good but not very flexible. No matter where I set any of the knobs, it sounds pretty much the same. Does anyone else feel that way?