What other features annoy you about the sites? Or maybe you have a favourite feature?
Personally the ability to select multiple suburbs with a radius and then remove certain suburbs is great
Realestate.com.au and Domain have very different listing volumes.
They also have different audience participation and geographic reach. In some states the difference is as high as 50%.
As others have already mentioned, in other states neither of the above is the dominant portal.
Allhomes is strong in the ACT, Reiwa in Western Australia is big also.
Many people know they need to search multiple sites to canvas the entire market and the data shows that many referring sites are actually each other (domain to Realestate and vice versa) as that user goes from one portal site to the next because of this exact reason (check all listings, some agents list on one and not the others etc etc).
There are 40 million Australian searches for real estate related terms on google every month. If you're looking to list with an agent in a particular area, perhaps see who dominates the search engine space in that particular area as a starting point.
From my own perspective, I would also like to hear the likes/dislikes of the current portals in terms of features as we are always looking to improve our offering.