I have a Velodyne DD-12 on order. In addition to being a very good, musical sub (which actually lets you adjust how "fast" it is with the servo), the advanced analysis and EQ potential seems like a very good addition. It really lets you find, and correct for, whatever room/system anomalies you have going on. But most of all, they sound great. Very tight and musical (or slow and boomy, if you want that).
Tom.
Tom.