Very comfortable.  Flush is strong.  The flush is somewhat loud, but only for a second.  I'm giving it 4 stars for the same reason I gave the elongated seat 4 stars: the top of the toilet tank does not stay properly aligned.  I think the elongated seat pushes against the toilet tank and slightly misaligns it.  It's minor and doesn't cause exposure of the tank itself, but it is kind of annoying from an aesthetic point of view.  Overall, I'm very happy with the purchase.  I just realign the top of the tank when I have guests over.