Some people are inclined to believe that one is clearly superior to another based off of cost. The old idea that if it is more expensive, it must be better. While there are some companies that are all about cheap (low cost, low quality), most people that are even slightly open to logical thinking would agree that they are the same in usefulness with the Axiom line. It is more of an "inexpensive" thing (lower cost, good quality).
As is also mentioned, there is a different look to them too. So the upgrade cost may be worth it, whether within the Axiom line or compared to other manufacturers (see, we aren't all "fanboys" here).
M60s, VP180, VP150, QS8s, M3s, SVS 20-39PCi, Shakers