Ah, thank heaven for the internet; it saved us from buying a poor-performing toilet! All the reviews on this site and others convinced us to find and purchase the Toto Ultramax (we had been looking at the Kohler Santa Rosa at our local home depot). Boy, are we glad we did! We have very low water pressure, and plunging used to be routine for us, but the Ultramax seems to be uncloggable! We will definitely be replacing the other toilets in the house. Our only complaint is we don't find the curved seat to be very comfortable, though maybe it just takes getting used to. Also I notice that inside the ring there is an edge which I find to be somewhat uncomfortable. I do love the soft-close feature, though. I notice no one else on this site seems to mind the seat so maybe it's just us. At any rate, the seat does not dissuade us at all from replacing the other toilets, because the seat is easily and inexpensively replaceable. The unbelievably fast, powerful flushing far outweighs any concern over the seat. We bought the elongated, and we think we may try the round in another bathroom.
In short, LOVE this toilet!