The EP500 is a very strong performer for it's size. I was surprised at the power that little box has. I would also look to Paradigm DSP3200 or 3400 for a good sub without breaking the budget.
But to cut through some of the confusion, I would highly doubt you would be able to say that you felt you were missing any thing if you went with any of the manufacturers offerings that you have mentioned.
BTW, you should come back for another audition, I realized I played that depth charge scene from U571 with DD instead of the more dynamic DTS, the house really shakes with the DTS soundtrack.
