If you look at the dimensions you can easily see if Polk Audio CS10 Center Channel Speaker will fit into your existing setup or not, If you are expecting some tiny little speaker that you can tuck away this is not that, but at the same time its not all that big.
As for the sound from Polk Audio CS10 Center Channel Speaker you would say it is very good, it may be a tad nasal on some male dialog but this is slight and does not take away from the over all sound quality which produces nice clear highs and very good base response for this price range.
The build quality is top notch, the weight the construction this is a solid build right down to the black lacquer sides, no cheep plastic here. To sum it up Polk Audio CS10 Center Channel Speaker is a great buy, and you really can't go wrong with this purchase.