Let me start by saying that sound is one of the most subjective things in the world. What sounds nice to you, may sound bad to me and vice versa. There is no objective way to rate the sound quality other than efficiency, distortion, frequency response, etc.
The Klipsch has a slightly wider response and larger woofers. It is also 8db more efficient, meaning it will be louder when given the same power as the Mirage. Both sets of speakers have metalized cones and tweeters giving them crisper sound due to less flexing of the speakers, as well as the natural resonance of metal (tap a piece of metal and a piece of plastic, they sound different and those properties “color” the sound of your system).
So as for the subjective part, I am ALWAYS a fan of matching the L, R and Center Channels closely when it comes to frequency response and efficiency. As something moves left to right it will hit all three speakers and it should sound the same going through them. Using the Mirage will help that.
Clarity is interesting. First, make sure you adjust your subwoofer crossover down below 65Hz. Some subs go up to 100Hz or more. If you have dialogue or score in those lower registers, the subwoofer will muddy it up. Subs are non directional and seem to come from everywhere. You want your brain to associate speech with the direction, and letting the sub play these sounds minimizes that.
The Klipsch center has a horn loaded tweeter. Cup your hands over your mouth and yell. . .do it. . .now! Now remove them and yell again. What sounded more natural, and what traveled farther? The Mirage will give you a smaller sweetspot, as it is omnidirectional, and it will also have a more natural or open sound I would argue. I like Klipsch as well, but my personal preference is a more open natural sound. Klipsch gets loud fast, Mirage takes its time.
I hope that this helps. I think you will get the desired result replacing the center, given the rest of your system components.
Best and God Bless.
Orange Pro AV