I A/B'd them as best as I could, I do not have the fancy switches and stuff, just turn off, plug in and back on, as fast as possible by a helper, I did this through many different movie scenes and musical varieties. My results could have been due to room acoustics, but I did the same tests at a friends 4000cf room as well and we both agreed with my initial findings even in his room. We did an EP600, EP350v3 and the DLS-5000R at his house and the EP600 is definitely the best sub Axiom makes and that isn't saying much considering you can get the PB13-ultra for the same price(Hopefully I will get mine in a few weeks). The EP350v3 gives the big Ep600 a run for the money and wins because it is less than half the price which is why I said if I were toget an Axiom sub it would be the new EP350v3; it's the best bang for the buck from Axiom. It even gave my PB12 a run for the money sound wise, but you could tell the PB12 for $100 more is still the better choice.
The Axiom subs are dated in their technology and it seems Axiom is happy with the way they sound, which might be why they won't answer you Mike, they feel there is nothing wrong with them
If they cut all of they're prices in half then they might be a reasonable choice. It is a sad state for such a good speaker company, then again look at what the rest of the speaker companies subwoofer offerings, not many offer really good subs either.
Like you said, and I briefly touched on, the Axiom subs do not like to be run loud, usuall listening SPLs work but when you want to really crank it up they are not the ones to do it with and lets face it, the max SPL they are rated at is lower than the competition. I know many of those with Axiom subs really like them, its just us bass heads that seem to not like them as much.