If this rumor is true, it would explain why Mirrors Edge was featured at Sony's Playstation Day in London earlier this year.  It seemed odd that a multi-plat title would be featured by Sony.  I really hope that this is not true.  I don't think timed exlusivity deals are good for anyone.  Sony would be better investing their money in first party development.

"According to Reeves Mirrors Edge will initially exclusively for the PS3 this year. The PC and Xbox 360 versions would follow much later. "

http://n4g.com/News-187773.aspx

Timed exclusives only hurt the developer.  They release a game, then after all the hype is gone they try to release it for another console.  Only worth it if Sony or Microsoft pays you enough to make up for your loses.

I guess it's good for the platform holder to make their exclusive library seem a little stronger than it really is, and good for the developer to get some guaranteed income. It is definately not good for us.

Isn't it being developed with the PS3 as main platform?

I'd have picked a different game, but I hear Mirror's Edge is a good game. If Sony wants to crush Microsoft, the need to go after titles like Tomb Raider, RE5, and Prototype.

 You'd be a fool to buy the 360 version if you have both consoles anyway.  It's being developed on the PS3 and will almost certainly run smoother or the same, or look better or the same.  360 can run worse or the same, or look worse or the same.  You have much better chances with the PS3 version.

@lewis
I don't think Tomb Raider is that much of a heavy hitter anymore, but I couldn't really say.  And Prototype isn't looking any better than Mirrors Edge, I'd personally rather have Mirrors Edge.  I'm not saying Prototype won't be good, it probably will..but that's just my preference.  RE5?  Yeah, but you have to consider that RE5 would cost more than Prototype OR Mirrors Edge in all likelyhood because it's an established title.

Have you seen the new Tomb Raider trailers? The game looks god-awful. Sony also have their own first party third person action-adventure game (Uncharted:Drakes Fortune).

RE5 would be beyond the budget of either Microsoft or Sony. I reckon you'd be talking well over 100 million dollars on a single game, simple because it's a sequel in a very popular and critically acclaimed franchise.

Prototype- Again Sony have their own first party title competing in this bracket (InFamous).

It makes sense to me, Mirror's Edge really is a very unique looking game and Sony have no first party games under development that are even remotely similar to it.

EA could be worrired that the game, as a new and unproven IP, won't preform very well sales wise, so are more than willing to let Sony cover development costs and in turn they release it on their platform first.

I was also wondering why Sony showed a trailer of the game at GD.