The one good thing about the current subsidies over the last one is that now as I understand it it is available for any property investment, or primary residence whereas it used to be only for your primary residence.
One of the best sites I have see is: http://www.energymatters.com.au/
The current prices for systems fully installed in SA are: 1.41 kW - $3,229 1.64 kW - $3,789 2.115 kW - $5,744 2.82 kW - $9,409 5.17 kW - $20,654
To me the best value for money systems are upto the 2.115 kW system because of the subsidies. However the 5.17 kW system would probably meet a households overall annual electricity usage - bearing in mind you would likely use more in winter (at least for my circumstances) and would be a net exporter of electricity in Summer (getting paid at the higher feed in tariff rates).
With respect to Air-conditioning 2 years ago I replaced my home evaporative air-conditioner with a Breeze-Air evaporative unit and haven't looked back since. Then last year I install different size Breeze Air units in the rentals and again they have worked great with low costs.
