Summary: I've not had a 5.1 setup so I don't have much to compare against, but I put together a home cinema with this speaker as a centre. Seems great. There is a plug in the rear port which I think is a phase plug - anyhow, mine sounded better in my setup with this removed.
Summary: Excellent product. Big enough to function but not visibly obtrusive. Gives excellent vocal signal, but does need a bit of oomph on the amplifier to get the full sound picture. Overall, I am very happy with my purchase and would recommend both the product and merchant.