When I hear that any exclusive is going multi-platform I always take it with a grain of dread. I have no real "loyalty" to a platform but I understand there is something special about an exclusive. The difference between the 360 and the PS3 is fairly large when it comes to developers. The best part about PS3 exclusives I think is the fact that developers have 50 gigs (They expanded bluray's size recently) to play with. If that company wants to make more money they may "dumb...
I own a 360 and the PS3. I honestly think that having both would allow me to open my gaming library up to the best of console gaming for this generation. I had a 360 for years and recently bought a PS3. I loved Fable 2 and Mass Effect and will buy their sequels. I also loved MGS4 and Uncharted. I have yet to play Uncharted 2 because I have not yet beat Uncharted.
I'm starting to think that regardless which system you have, the exclusives are where it's at. Those may be the cream...