The Bottom Line: If you are on the fence like I was, rest assured that in this price range ALL the subs are great. I can personally recommend this one though.

I decided to upgrade from a Boston Acoustics XB6 subwoofer a couple of months ago. At the time, I wasn't sure what to purchase to make my move up to a upscale subwoofer. I looked at Sunfire, SVS and Velodyne and I'm sure any one of them would have done a fantasic job of supplementing the bottom end in my home theater.
The problem with those said brands is that it's nearly impossible to audition those locally. I wasn't about to go through the hassel of internet ordering again, as I've had that headache in the past and have become leary of handling practices.
So I looked online at local retailers and found this to be the best or at least most expensive that anyone had to offer.
I had auditioned DefTech subs previously and knew that the bass was deep and tight. Perfect, that's just was I'm looking for!
So I drove to UE for a first hand demo and was again extremely happy with the performance of this unit. It added a huge amount of depth and rumble to the best and biggest pair of Klipsch the retailer had in house. I A-B'd the setup with the sub on and off numerous times to get the full impact of what the subwoofer would be able to do within a working system and within minutes I was sold.
I somehow lugged this 75 lb. tank into my living room and proceeded to set it up. I first auditioned some music....meh.... it was o.k. , then I auditoned a movie (Fantastic Four - Silver Surfer)
It again, was simply o.k. So it had me wondering what the heck was going on?
I proceeded to pull the owners manual and read. How ingenious?!!!!!!
I hadn't noticed there was a low and high pass adjustable crossover as well as a continuously variable phase select. Long story short, I adjusted all three controls accordingly, popped in a well known and bass heavy scene from Lord of The Rings and WHOOOOOAAAAAAA!!!! I thought I was gonna bring the building down, I had to dial the bass back to -6 db on my Denon to keep from shaking the walls down. After the dial down I listened and auditioned some more, making minor tweaks here and there until it blended seemlessly with just the right amount of what I like to refer to as "gut punch". All in all what a great purchase. Yes it was expensive and I felt kind of strange putting down that much on a single subwoofer, but now I understand why the pricey subs sell for the money they do.
(1) 10" Sub Driver
(2) 10" Infrasonic Radiators
1500 Watt Class D amplifier
1" thick sound board
Piano Gloss Black finished Cap
LFE, Low Level and High Level Gold Plated Inputs

What more could a guy want? It fills a 12x15 area (that is adjacent to a 5x10 area that leads to a hallway.... really an acoustic disaster of a setup...) to extreme Bass SPL and does it without a hiccup. Nice indeed.