I downloaded the game on both the PS3 and the 360 and played both at the same time, just now. I had both consoles set at 720p using component cables and on different channels. Switching back and forth, I must admit that the PS3 version looks just a teensy weensy itty bitty bit better (you have to REALLY be looking for differences, though). The PS3 version "shimmered" less, and there were a couple effects that were done better on Sony's console.
The placement of the "Batarang" and "Spider-sense" (I don't know what else to call it) were in better position on the 360 version, though. I usually go 360 when it comes to multi-plats, but this time the PS3 version is the way to go.
With this playthrough, I was a real bastard! I wasn't afraid of the bad guys anymore. I was following them around, popping up from the floor, and really freaking them out. At this point, this game is my most anticipated game of the year!