That's a funny question - really. Best for what?
Finding gold is all about conditions, access, research, hours on the ground bla bla bla....horses for courses as they say. WA, Pilbra = thousands of square kilometers, open, baron, remote, less people more area to cover. Could take you a day or years to find anything, and can also be rewarding.
As much as I hate to mention it, Aussie Gold Hunters portrayed the W.A. detectorists reasonably well. The Victoria detectorist, Poseidon crew, was all planted except for a couple of times. You guess it, the times where the found next to nothing. I know, I have their exact locations (don't ask) and have been over the areas they filmed.
Victoria GT, more concentrated area so easier access - for thousands of people to look. No such thing as new ground (as opposed to virgin ground), we only have a few hundred square kilometers and that's it. Good gold here too, if you are willing to put the time and work into.
Everyone needs to invest time and money to gain research required to find gold. The more I learn, the more I find through education and experience.