I have compared the Paradigm SP3100(10") to a EP350v3 and the little paradigm held it's own for movies and was as good for music, IMO. The DSP3400(I haven't heard one in my house) should be as good or better (sorry Axiom) than the EP350. The EP500 has quite a bit more low end thump for movies than the EP350, again IMO.
To be honest I think you would be very happy with any of the subs being mentioned as the differences are really only noticeable when A/B'd, as long as the driver sizes are equal. I can usually tell when a 10"sub is playing during good LFE scenes in movies compared to 12" subs. That extra displacement is required for authoritative low end rumble.
