The dilemma being the other Mass Effect games aren't scheduled to be on the system yet.
There are rumors that Mass Effect 1 will be showing up on the PS3 at some point but those haven't been confirmed.
If the Mass Effect games end up on other consoles other than the X-Box that will help Bioware's botoom line although the fans don't seem to like the third game very much.
Some say it's a failure like Dragon Age 2. They blame EA.
Rather sad such a good company has fallen so far.
Dragon Age 3, which btw wasn't mentioned at E3 may be Bioware's last chance to turn things around or heads might very well roll at Bioware.