I don't know about the benefits we'll get from it ... we'd have to wait and see.
But it seems like Microsoft is starting to realize they need to cooperate with more people (including the open source community as seen by their recent actions in making some source code available (though it is only a little)), and that they can't dominate the world. It's about time! I think Sun should have made them beg on their knees a little, but oh well... Hope it all works out for good at some point.