Well, the IDQ is hard to beat for flat out SQ, especially for that price. But, its also a bit of a specialty subwoofer, you dont see alot of people asking about them. Usually if you are interested in IDQ's, you already know what you're doing and what you want. IDQ's are extremely SQ oriented for extremely small sealed enclosures. They're not meant to impress anyone's buddies by blurring their vision, and they're not meant to pack into a large vented enclosure with tons of port area. If you want a little more output from your sub (little more SQL than SQ) or if space isn't such a limiting factor, Id suggest looking into the IDv3 from ImageDynamics, or the Oz Matrix Elite, or a few of the others mentioned above.