The double-cyclone gives better bowl wash. The 1.28 vs 1.6 gallon flushing on the Totos is pretty close, I would opt for either depending on the style and what was available. All toilets will eventually be 1.28 or less. I seem to remember that the Gwyneth/Ultramax naming thing, but not sure of the details...I think they are the same thing. Just like Ford changed the 500 to a Taurus to keep the name recognition, I think Toto dropped the Gwyneth name.