Nousaines numbers are skewed. I had the PSW 505 for 2 years before I bought a Supercube.
There is no comparison. The Definitive Sub puts the smackdown on the Polk sub and then rips it's head off and craps down it's throat.
It also smokes the SVS sealed cube sub so don't get caught up in the I.D. fanboy hype.
If you want more bass than a small cube can deliver, you'll need a much larger cabinet at the very least and it you want truly prodigious bass,
you'll need to spend more money and start looking at Fathoms or the like.
The Supercubes and Sunfires are tremendous subs for their size regardless of what anyone else on this site would like to have you believe.
Not everyone wants a big ass ugly box hogging up precious space in their household.