It's always been made with Multi-platform in mind but it heavily favors Xbox and always has. I've never played a UE3 game on PS3 that felt good. Not once.
I haven't played the demo yet (so much stuff to download on PSN this week!!!), but it seems the PS3 version is not comparable to the 360 right?
Man, I could search the post I made some months ago predicting this, but since everyone and their mother knew that would be the case I won't waste my time...
Truth be told, there are good PS3 versions of UE3 multiplatform games. Dishonored fells great, plays great. And I'm pretty sure both console versions are almost the same. Differences are negligible.
Too bad Ninja Theory is just not as talented as the folks over Arkane are. After the horrible port of Enslaved for the PS3 this was pretty much a given.