Ok so I have just played the first couple of hours of the 360 version and it was absolutely wonderful. The game establishes the world so gracefully and doesn't rush to appease the player at all. I certainly don't want to spoil anything for anyone so I won't talk in any detail but it gave me the same feelings as when I was introduced to City 17 for the first time.
My only major gripe so far is frame rate. You can disable V Sync in the options menu so they obviously know its a problem. Too many enemies and I felt like I was hitting the low 20's which was not great. Also had a few texture pop in issues but thats nothing new as its a UE3 title.
4mb day one patch too which installed before I started.
The thing thats making me want to do an all nighter though is the writing. Story had me hooked in the first ten minutes.
From this it sounds like the ps3 version is better.