The price?
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Compared to the original US release, netlink and 3D controller support, slightly better graphics. The original EU and JP releases had the graphics, and the Japanese Plus added support for the 3D controller.
3D controller support isn't really interesting imo. The port was designed for digital inputs, analogue doesn't add anything, except maybe jittery controls. I didn't like it at all.
If you can play imports, don't bother with either American release. The cheap one was rushed and the expensive one is expensive. Get a Japanese disc, everything is in English like every other SEGA arcade conversion. If you can't play imports, the difference between US and JP are minutes and the gameplay is intact = it's still a fantastic game. Don't get the PAL one unless you're in PAL land playing on a PAL console. It's optimised, and well optimised: the additional scan lines show more of the scenery and the timing is identical to the 60Hz version, but the bottom of the screen will be cut on a 60Hz console.