Ok, so I'm home, sitting here A/Bing between the O2 and the Beta22, each being fed by a laptop into a Cambridge Audio DacMagic, with Angel Of Death going the whole time. Verdict, the Beta22 is much clearer, I can distinctly hear each guitar, sounds more like I'm listening to instruments, rather than a recording. The O2 has a much narrower sound stage, less separation between instruments, less channel separation, and the high notes hit in the guitar solos sounded brittle.
I choose Angel of Death a while ago as a test song because it's got a lot going on, and can come off sounding like a mess (which is part of the appeal), so if a piece of gear can "clean it up," then I'm pretty happy with it, which is part of why I love my Beta22. Now, do I hate the O2? Nope, I'm not head over heals for it either, but I'm going to spend some more time with it, figure out it's strengths and weaknesses and go from there.
//end subjective test of objective amp.