Need help to buy a subwoofer?

I am planning to buy a subwoofer. I need help to choose from: (1) Sunfire signature with auto EQ, (2) VELODYNE DD18, or (3) Paradigm servo15 V2. Please any information will be helpful. Any other recommendations?
Martin Logan Depth or Descent
I'd buy a Vmps or M&K. A new Vmps has great bang for the buck and is why I became a dealer for them a few months ago. Do a search and check out the user reviews on Also used M&K's here on Audiogon are great deals. Both of these are fast, powerful and musical.
I'm biased - I own the Velodyne DD-15 - but I'd go for the Velodyne. They're good looking, very adjustable, and lightning quick. That said, all I can vouch for is that I like the Velodyne - I've never heard the others on your list. -Kirk