When I had my Aperion front stage 6Ts and 6C I came across this article and did some research on my
own. http://forum.blu-ray.com/speakers/89614-horizontal-center-channel-speakers-why-they-should-avoided.html and it did sound better having 3 matching speakers.
If you do not have room then get a horizontal. To my ears 3 perfectly matched speakers sound better. really a seamless front stage.