I'm not saying it is better than the Warden but meh. The Solo-X has been around for a long time and it's been proven that it can take SPL abuse. Two 12" solo-x can pound out 155+dB on a termlab. Go ask the people on Termpro's forum and they'll tell you the solo-x is a beast. It is standard for people to mate one Solo-X to a Kicker 2500.1 and I've installed two running off of an USA-2000X and they don't even sweat. Besides when **** goes wrong it is much easier to recone a Solo-X than the Warden since you don't have to send anything in.
Solo Xs are loud as he ll, but I have a heard time thinking that they are the loudest. In all honestly there are a handful of subs that given the right enclosure and gobs of wattage will wake the dead...DC Lvl 5s, DD 95/99 series, Treo CSx, etc etc etc