Holy crap, I HATE it when I stumble across another subwoofer webpage, they always make me rethink my Axiom choice.
Take for instance the Epik Conquest. 1000 watts of power pushing a single 18 inch driver down to a claimed 12 hz, for a couple hundred less than the Axiom EP600. Does it sound as good as the Axiom? I have no clue, but the propaganda write up on their site sure makes me wonder. Then there's the Element Design A7 - 900 beast... 1300 watts pushing twin 18 inch down firing drivers in a monsterous 435 pound package, Jesus Christ!!! And at $2200 bucks it is in direct competition with the new EP800, only it packs more than 50% more power... gosh how does a guy stay loyal???
Perhaps I'm too superficial, but those subs don't look to have the build quality, R&D, or quality components to truly compete with the Axiom. I don't have an Axiom sub, I use B&W, but there have always been garage sub companies for car and home audio. And all are not equal. For those subs to be priced in the Axiom range tells more that Axiom is well priced than the quality of those. Most of the subs you cite look like they could be built in your garage with better parts - (like non-Bash amps, and drivers with real magnets). Compare to something like a JL
JL Parts or B&W
B&W or other known sub entity. Some cost is just marketing and name recognition, but some of it is quality and R&D. $2,200 is not cheap, to me anyway, and I would be hesitant to drop that on a complete unknown. Axiom is not traditional, but clearly not an unknown. Not saying there are not better values, just that every multiple driver 1000 watt sub is not created equal. Heck, see the highly acclaimed Gotham and check the price for a true high end dual driver high watt sub:
JL 
