the truth be told, with 2 of either of these, the difference in SPL will be minimal at best. I doubt you would be able to tell the difference if everything else is the same. Your talking about 6800+ to 7500 watts, the 600-700 difference will not add up to much if anything, maybe a 10th of a db.
I personally would go on the fact that Sundown is proven in their power, reliability, Customer service, and the fact that incase of the odd failure, the repair shop is already in operation and doing a fantastic job (thanks dB-r).
Although AQ seems to be right in line, they are not proven with their version of the Zenon amp and the repairs are not in full swing and proven, at this point.
Just my honest opinion.