I'm new to subs so I can't comment a whole lot. I listened to both the EP175 and EP350. The 350 was, to me, very good in the 12 x 20 x 7 room I was in. The 175 was underpowered.
If you are in the US, you have a lot of good choices with svs and HSU. A number of people are also raving about a new AV123 15" sub that is only $599.
If you want a small sub, a lot of people also thought the SVS PB10-NSD performed very well for the price ($429). I don't know if HSU or SVS have an auditioning program like Axiom's. It would be nice for you to hear a couple of subs before you buy.
