Talking specifics here .e.g. Daikin Cora 5kw vs. Mitsi Ecocore 5kw v Panasonic Aero 5kw v Other 5kw?
Not much between them specs wise, all pretty efficient for this size/model - Daikin and Pana 4/4.5, Mitsi 4/3.5
Panasonic $500+ cheaper than Mitsi, a bit more again for Daikin.
How to choose?