That is a great deal. The Axiom subs seem to get good praise and the DSP chips (some models) looks to be a real benefit over the more typical amp+box approach. But there are many others you can find on this forum that make very good subs. Your budget will drive this more than anything, as price is almost unlimited on the high side, but the floor for quality is not. The used option is very good, but check it out first. It is easy to abuse a sub and drivers are mechanical devices so be sure it works before you buy.
Good point on buying used to be careful and give it a good test before buying. But if you buy from a reputable dealer, they should give you 30 day warranty at least. In fact, I vaguely remember my Paradigm dealer told me that any Paradigm he sells carries a full warranty used or not. Like the others have said, the brand is not as important as getting something 'above' the minimum quality floor. When you start hearing some good subs, you'll get a sense of what SQ vs. cost fits for you. I love the used idea, because I, especially at this economic time would be able to spend $1,800 plus on this level of sub new. YMMV
