Art is terribly subjective while simultaneously being very dependant on the 'angels in the architecture.' (To loosely quote Douglas Jones & Douglas Wilson.) That is the firm structure of shape, symmetry, colour, texture, content to style relationship, tone and perspective which provide glimpses of beauty as how it should be but isn't due to the Fall. (My Dad who among other things paints oil portraits knows much more about this then I do.)
The following two Archibald entries are the best in my opinion. The intriguing mood of the subjects is brought out by the use of perspective and tone, notice how the Aboriginal woman stands half in shadow. The genre of both sits on that wonderful border of realism without being photo-realistic.
[Self-portrait by Robert Hannaford]
[Nancy Kunoth Petyarr by Jan Williamson]
I was thoroughly disappointed by the following portrait. Note how it's difficult to establish a theme of the subject, the general lack of structure is reinforced by the garish use of colour. There is also no spatial depth which gives a slight incoherence to the entire picture.
[Portrait of Nell by Richard Larter]
This one deserves a mention, having a Tassie theme and all. (However I find the composition unsettling.)
[Coupe SX010F by Richard Onn]