OK, again based on a couple of specific requests, here is one more clip of the AE212 and Thunderchild. I'll leave this up for a few days until they've had a chance to see it.
One thing I guess I should mention about all of these clips. I record them at LOUD volumes in the room... gig level volumes. I feel this is the best representation of what a cab actually sounds like. Due to the autolimiter in my little recorder, my talk over is always a bit low volume due to how loud the cabs are, but I feel that is a small price to pay to really hear what these cabs sound like when, if not pushed to their limits by any means, at least cranked up to 'typical' moderate gig volume (and by some definitions, loud gig volume).
Notice how much brighter the AE212 is up top, but that I can make both cabs sound (IMO) quite similar by either pumping up 800hz with the Thunderchild, or cutting at 2K or so with the AE212. The F500 with those dual semi-parametric EQ bands is very nice. The EQ on the MB heads is designed in the classic 'EQ sense'... designed to be powerful but subtle... not really meant to 'make the head sound different than its inherent tone, but rather to 'equalize' that nice even tone across different cabs and rooms. I love it.
blah, blah, blah... here you go

(And a nice picture of these two cabs together a few posts prior to this one).
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Edit: FYI, tweeter is at noon on the AE212 and 'flat' on the Thunderchild (i.e., not rolled off). Interestingly, most of that brightness in the AE212 is coming from the top of the drivers, not the little tweeter, so dialing the tweeter down has only a minimal impact... obviously less upper treble, but the upper mid/lower treble 'brightness' remains.