Its good for them. As CommonMan mentioned, developers were more or less forced to do this though. It is far easier for them to build a game on the more complicated PS3 infrastructure and then port it to the 360 (being easier to program for) than it is to take it the other way around.
However, this does not always mean the PS3 lead platform games will look better than the 360 versions. In fact they still tend to look about the same if not slightly better on 360 in some cases.







