I've installed dozens of Caromas and Aquias.
The round front Caroma is 28-1/4" long and the elongated is 30-1/4" long.
The elongated Aquia is 27-1/4" long, takes up less room in a small bathroom.
They both flush well,
They both have a small water spot, small but deep.
The glazing on the Aquia seems to stay cleaner.
To install any new toilet, you will need a seal (wax), attachements, bolts or screw kit (for some Caroma models) and a supply.
I normally order Aquias twenty at a time, and the Caromas two at a time.
Either toilet works well.