I was also at the PDX GTG, and we had the Thunderchild next to a Genz Neox 115 (or was it a 112?) and a small Acoustic Image cab. The Thunderchild spoke much more clearly, and with more projected "strength"; IOW the other two cabs sounded
good, but they didn't reach out and grab me nearly as much as the TChild. It didn't have a huge round low end per se, but the lows were present and accounted for, and were fairly well balanced with the highs. At least given the playing and EQ that I heard tonight, I would peg it as "noticeably better than a typical 210 or 115" for people who play cleanly, and who don't need to fight with the drummer and guitarist.
When we put a 12+6 fEarful next to the TChild, the fEarful stomped on it, with much bigger low end, and more perceived strength. However the fEarful was (at a very rough guess) almost 2x the cubic volume of the TChild. So just based on this limited trial in an "at home" setting, I would prefer the 12+6 fEarful as a standalone cab if I needed more
loudness; but I would prefer the TChild if I needed more portability.
If my guess about their respective volume is even
close to correct, then what I'd
really like to hear is a pair of TChilds stacked vertically.