apparently the ps3 version is overall slightly better plus the free joker content on ps3. See a good comparison here with proof:
http://www.lensoftruth.com/?p=14110 (site loads slow)
edit: but this comparison of the demo says the 360 demo is better… :confused:
http://www.eurogamer.net/articles/digitalfoundry-batman-demo-showdown-blog-entry
The PS3 version of the game looks better than the PS3 version of the demo. I’m not sure what happened, but it might have been better optimized after the demo.
Honestly though, the games look nearly identical. The difference (if there is one) between the two is so slight that you can’t really tell when looking at screen caps. Get the game on whatever system, but I think fans of batman should get the PS3 version because it has the Joker content. The Joker content is just challenge rooms, but he does play different enough to warrant it’s existence.
And as far as I know that’s never coming to the 360.