Definitely GA, however it was once regarded as the high end of GA but now that has all changed. Why? Mainly because it has become highly corparitised, the flying hours have trebled in only 15 years or so and most of those are due to heavier demand for interhospital transfers (ie air ambulance/patient transfers).
What that means for the average RFDS pilot is (a) they are flying a lot more mostly P3s (over 90%) and most of that is on the backend of the clock. (b) most of the prior extra benefits have been eroded eg company car with unlimited fuel card, subsidised rent (have heard 20 dollars a week was not unheard of) with no or very little amenities to pay.
Although you can say they are only GA, RFDS pilots on the whole are still required to be trained and current on some of the most challenging forms of IFR flying ie limited flare, road landings, marginal strips, high performance, single pilot, multiple diversions etc. I believe this requires a pilot with a high experience level and knowledge of aviation extremes that the average GA charter pilot just doesn't have.
So you could argue that the guys at Westops have a pretty strong argument to be bleating about a major payrise. The fun an nostalgia of working for an Australian icon has all but eroded it is now just a hard slog! I know I used to work for them!