The Caroma Sydney is a Watersense toilet.
However Seattle Water isn't offering the rebate right now.
The bowl is the same for both the standard and the low profile, so washdown on the bowl should be pretty similar.
The Toto Aquia has a better bowl wash, and the Caroma has a bigger trapway. The average person doesn't need a trapway that large, but there are some medical reasons why some may.
Caroma Sydney in the Seattle area
Caroma Sydney with 270 bowl.