We've had a 5 zone 10 outlet Fujitsu single phase inverter unit for about 8 years now.
Faultless running and very quiet. Cost at the time was a shade over 8k installed.
Would have no issue doing the same again.
Jeff Mouritz did the install.
http://www.gasair.com.au/home.html
We had Daiken come out and quote. They seemed more interested in commercial units and fleecing people of money.
GL.