Hi,
I can the Definitive Reference sub and it was amazing. When I went to the store to see it they only had SuperCube 1 on display and I was shocked by the power of it. I figured since the Reference model was still in my price range I'd do for. However, later I purchased the Axiom EP600 and the difference was night and day. Even though the Definitive Reference model out amped the Axiom the "sound" quality of the Axiom just blew it away. If I were looking for a sub today, and couldn't afford the Axiom EP600 I would absolutely checkout one of the smaller ones I'm sure you would not be disappointed. Like speakers there is a difference with how sub deliver bass. I found the Definitive a powerhouse, but the Axiom cleaner, and deeper.
In terms of an amp.... check out Yamaha. After going through 2 Denon models, one better than the previous I found them to be less satisfying, almost muted by comparison with other amps. I heard a Yamaha demo and thought the sound was clearer and the imaging, especially for movies, more direct and noticeable. In the end I purchased a Sherbourn processor (which by the way I'm selling) and currently awaiting an Anthem.
But getting back to the sub - I'm sure the same quality and "sound" that's part of the EP600 is shared with smaller models in the line. I don't think you can go wrong.
