One Canadair CL-415 - two engines, two crew, 6000lt capacity, about $20m.
Requires good airstrip and suitable water source for scooping close to fires. Single role aircraft. I don't think you'd get a SAR contract that also allowed you to go off and fight fires.
Two AT-802's - two engines, two crew, 6000lt capacity, about $3.5m.
Requires ag strip and suitable water source close to fires. Can be tasked to two fires or staggered on the same fire.
Multi-role aircraft so it can feed itself outside fire seasons. Probably why they are selling and 415's aren't
The major issue is not what aircraft are used, but how they are used. NSW unlike SA, VIC & WA do not use aircraft for initial attack. They have not invested in airstrip infrastructure in strategic locations, like SA & VIC have, to allow for an initial attack policy. In the Adelaide hills an aircraft is above a fire within 10mins after a smoke sighting on a high danger day.
In NSW the policy seems to be to let it get good and established so the federal money starts kicking in and there is lots of publicity. The difference could be that SA & VIC have lost many lives in the past (Ash Wednesday & Black Friday).