The Region 1 release misses out on:
The Region 2 release misses out on:
The Region 4 release misses out on:
The Region 1 disc contains both a widescreen and Pan & Scan transfer of the film. Some sources suggest that the Region 3 release has DTS ES 6.1 audio, but contains only a Pan & Scan transfer of the film.
I found the Region 2 disc to have a slightly lower average video bitrate (8.7Mb/s) than the Region 4 (9.0Mb/s). Also, the Region 4 Commentary tracks are encoded at 224Kb/s, whereas the Region 2 tracks are 192Kb/s. These are not compelling differences, but worth considering.
The clumsy Region 4 layer change is nothing short of criminal in my humble opinion, when compared to the Region 2 layer change which is placed at 53:09 in a relatively silent moment. If you're happy with a lower video and commentary bitrates, then I would recommend the Region 2 for purchase. Otherwise, get it where you can find it cheapest.