As long as your L/C/R speakers have a similar general "character" to the so-called Axiom sound, I would say it would probably be just fine. Of course, having all sepakers from the same brand / product line is ideal, but many people sucessfully construct a mixed-brand surround system. Especially, the timbre mating between the fronts and surrounds are not as critical as that among L/C/R.
I, for one, have a mix-brand system of the Hales and Axiom (with a Hsu sub), and am happy with the surprisingly good timbre match between them. But when I was shopping for the center cannel and the surrounds, I certainly looked for what I thought would be similar to my existing Hales sound. I ended up with the Axioms. Both brands have been touted for the "accuracy."
