I have a 360 and a PS3.
I think if given the choice, I will always choose the PS3 version for the following reasons:
1. I have my PS3 on HDMI, looks and sounds better than component with my 360. This might be due to my television, but it is what it is, VGA looks a little better but I don't have audio inputs that will work with that on my set.
2. I have virtually unlimited HD space on my PS3, while my 360 is almost full.
3. My PS3 makes virtually no noise, while my 360 sounds like a dustbuster.
4. While I prefer the 360 dashboard by a factor of about 1 billion to 1, I don't have a wireless adapter, and since I've moved my 360 into my living room, I don't have any connectivity. I also refuse on principle to pay $100 for the adapter which costs $5 to make.
I'm not a PS3 fanboy by any stretch and some people might consider these to be superficial reasons, but from here on out, unless it's a 360 only title, I'm going for the PS3 version.
I prefer the 360 controller over the PS3 dual shock, but that and the dashboard(no wireless though) aren't enough to get me to choose the 360 version.
I want this game to be great, but I think I might just rent it.