Paradigm's Signature Sub 1 is currently in store. I've done a quick setup (using the included Perfect Bass Kit) and must say...I'm impressed! Not only does this sub go low and loud, it's also incredibly accurate. It's managed to tame the quirks of our sound room quite easily, due to the fact that it has 6 (six) 8" drivers, carefully calibrated to provide some of the most accurate bass I've ever heard.
It's usurped the Reference Sub 15 in Demo Lounge 3 for the moment. Come in and have a listen!