As someone who spent a year in Oz (QLD) as well as my time over here, I can say that both systems have their strengths and weaknesses.
I found the QLD roadworthiness system a little weird - as Hasbeen suggested, it is perfectly possible for a road legal car to have not seen the inside of a garage for years on end!
The compulsory CTP insurance seems a good idea on the face of it, but I'd guess it does mean that some people are driving around on the most basic insurance, that doesn't even cover property damage.
The weakness with the UK system is with the registration plates that stay with the car for its life - no way to easily tell if the car is taxed etc. Not too bad now everything is computerised, but still a weak point, I think.
I had a different experience with random breath tests in Oz - I was once pulled over three times in the space of about 4 kilometres and tested (around Christmas), not once were any of my details checked, in fact I never even had to get out of the car! Blow in the tube, green light - on your way again. Nice and simple.
That said, that was nearly six years ago now, so I expect a few things may have changed.
Garry
1976 2.0 (soon to be 3.5!)FHC
http://reds-tr7.blogspot.com/