Definitely worth doing, depending on who is running them of course.
The Queensland Raceway courses you linked to look quite good.
I did the L1 and L2 defensive courses through these guys -
http://www.murcotts.edu.au/
As well as a couple of Motorsports specific driving courses and training. They dont seem to list them now, I'm not actually sure if they were through Murcotts or if we just booked through them or not.