Have got an Aussie built 2002 Diamante 3.5.
Its been great so far - had it since new.
Its thirsty around town - but have driven from Taupo to Auckland - really nursed it along - didnt exceed 100kph and didnt pass anything - got 7.5l per 100km. Works out at 37.6mpg in old money. Did this twice - so not a fluke.

They were more powerful and economical than a Commodore at the time.

Had a Camry 2.4L rental car recently - Wasnt greatly impressed. Was quite pleased to get back in our Mitsi. Goes like a scalded cat if you put the boot down....
Hopped in a (NZ new - Aussie built) Diamante taxi once - the driver said it had been great - no faults - He reckoned the Falcon and Commodores were always getting faults fixed up.

Brother in law also has a Aussie Diamante (fancier model than mine) - Has had it about 5 years - No problems so far - likes it - reckons he will just run it into the ground.

I suspect that the Aussied ones are a bit more robust than the second hand japan imports.
Aussies like to over-engineer and do things their own way. They actually exported LHD Diamantes to the states for a while.