The Region 1 version of this movie was released some months back — I bought a copy on the day of release, but haven't had a chance to watch it before now. Now I can compare it directly with the Region 4 disc. If you bought a copy of the R1 as I did, then I have some sad news for you — you'll probably want to buy the R4.
The Region 4 disc is missing:
The Region 1 disc is missing:
These differences are not huge, and weigh in favour of the Region 4 release. The big difference, however, lies in the transfer. The Region 4 transfer I have described above. The Region 1 transfer has poor shadow detail (dark shades drop off into black far too quickly: have a look at 44:49 and 75:54 for examples), and exaggerated colour rendering (as though someone turned up the chrominance). By itself, the R1 doesn't look awful, but if you compare it with the R4, then it looks dreadful.
I recommend the Region 4 disc unreservedly — I doubt I'll watch the R1 again.