The issue we had was that the max system size is 16 kw so we jumped effectively from 16 to 32 (i.e 2 units). I am unsure what other sizes are available (if at all).
As with all HVAC systems, the more zones / outlets the more expensive. We have 3 zones but have allowed for the ability to add 1 more for the kids to control their temperature when they are older. We have also spec'd nest thermostats to hopefully leverage on their smarts to be more efficient (the nests were not part of the 67k).
In terms of experience, our build is yet to finish. The price I gave was our contract price which was quoted about 18 months ago. I have used it a few times during the progress of the build and it is far superior to standard ducted systems. I can't compare to hydronic as I haven't lived in a house with hydronic. Most of the sub contractors that have been through the house also comment on it as well and the site supervisor (who has never had a system installed before on one of his builds) is impressed as well.
As a comparison, when we did our tender we also quoted a daikin system. That price was approx 30-35k from memory, however did not achieve the same output.
Thanks so much for sharing