I have a Barefaced Super Twin, and it puts out as much volume as an 8x10, but with better dispersion, which makes it sound even louder, and with better low end response.
I used to have a GK Neo 410 but I also felt the B string sounded weak in comparison to the E string, and the cab didn't quite cut it in a loud prog metal band, but with this cab that's no longer a problem.
Volume wise, there is much more SPL available with the Barefaced, while staying totally clean where the GK started to fart out, so this cab has been excellent for that, specially being a one hand carry, at 40 lbs.
Regarding your question about choosing one of these 3 brands, here are the points I considered when comparing the 212's of the 3 makers, Fearless 212, Barefaced Super Twin and Thunderchild 212.
*Perhaps the BF Big Twin would have been the closest comparison to the F212, but since the cheaper, lighter and smaller Super Twin is available with the same loudness and still enough high frequencies for my needs (slap and brightness in the attack for a metal tone), I dismissed the Big Twin.
I should clarify that I haven't heard all of this 3 exact models in person, so this is based only on the other models I've heard and on my understanding of all the research I've made, the reading of all the threads I could find on all of them, and extrapolating from the comparisons of other users, so anybody with real experience in comparing them is welcome to correct me if I'm wrong:
-Out of the 3, the AK has a little less low end than the other two, although it still handles the B string just fine, and the Fearless probably has a bit deeper low end than the SuperTwin due to the bigger box (it probably has about the same as the Big Twin).
-The Fearless is the heaviest, then the AK, then the BF.
-The Fearless and the BF both have wheels, while for the AK it would be a custom request.
-The AK has switches to modify the character of the mids and pluggable ports to change it's tuning and low freq. response, while the other cabs only have tweeter or mid attenuators or crossover frequency dials so the Ak is the most versatile of the three cabs.
-Volume wise, the Fearless and the BF move more or less the same amount of air, and the AK perhaps a little less.
-The Fearless is the biggest of them, and the other two have more less the same internal volume, just different form factor, with the AK being taller and a little deeper, and the BF being shallower and shorter, but wider.
-The Fearless is the most expensive, while the AK and BF could have more less the same cost (depending your location) when you take into account that the BF has the shipment included in the price but you would probably have to pay import duties, while the AK doesn't include shipping in the price. For me it was a little cheaper to get the BF.
-The Super Twin has less high end extension, only up to 10 khz (the woofer goes up to 4 khz while the center dome carries on from 4-10 khz but with less volume) while the other two go up to 20 khz. (Which again, for me wasn't an issue with the BF)
-The Super Twin is perhaps a bit more efficient than the other two, due to the driver's increased sensitivity, so it may sound a little louder with the same amount of watts.
So, to sum it up, I went with the Barefaced because it ticked all the right boxes for me, being the lightest, the smallest (along with the AK), the cheapest, and the loudest (perhaps along with the Fearless) of these cabs. The only trade-offs were the extra high freq. extension of the other two cabs, the extra lows of the Fearless and the extra tuning options of the AK, so for me those weren't as important as having the lightest and smallest possible single cab solution that covers my volume needs.
Now, just as a side note, and as something I didn't really take into account on my decision, but that if true, could be an extra bonus for the SuperTwin, is that since the driver used in the Barefaced, the 12XN550 has a claimed volume displacement of 550cc according to Alex, while the Eminence Kappalite 3012LF used in the other two cabs moves 496cc, that could mean that the Super Twin moves even more air than the other two.
The reason why I don't take this as a fact is that there are different methods for measuring volume displacement, so perhaps they are using different yardsticks for this comparisons. According to Mike Arnopol and Duke LeJeune, this is probably the case, but Alex Claber hasn't confirmed nor denied this, so it remains uncertain, but the point I see in favor of Alex's claim is that he was already using the Kappalite 3012LF in the previous generations of his BF cabs, so if he took years of R&D to redesign and change his entire line up of cabs around this new speaker, it wouldn't make sense if it were just for a marketing trick, and from what I've read about him, he doesn't seem to be that type of builder, dishonest in his claims, so my guess is there probably is something real about this statements, even if the difference is not as radical as it may seem on paper.
So these are the thoughts that led to my decision. Your case and preferences may be different so you may end up choosing differently, but I'm very happy with my cab and I'm convinced it was the right decision for me.
Either way, all three cabs have excellent construction, sound quality and customer service, so you would probably be happy with either one.
Sorry for the long post, hope it helps.