I think you should match your speakers all the way around, if you're going for a 5.1, or greater, surround set-up. Think about watching something like Black Hawk Down, where a helicopter is circling around overhead... you'd want it to sound the same the whole time, right? Not like a helicopter from the front, and then a Volkswagon from above when it sweeps around to the rear. Ok, maybe that's a little extreme, but you get the point, right? I've never heard either of the speakers you're talking about, so I'm not able to say which sounds "better"... that's up to your ears anyway. Just talking about the whole 'cohesive-ness' of the sound... stick with one brand.
mods, can we have a 'dislike' button ?