Biogen/IDEC Announce merger plans

Whenever I see two companies calling an acquisition a "merger of equals," I realize that things aren't going to go very smoothly. Someone has to call the shots and it can't be both of them. I really don't see how this makes sense from a business perspective. One company needs to take charge, and it isn't clear that Biogen needs a partner that isn't a bigger marketing powerhouse than themselves. I'm sure Serono is doing a happy dance at the moment.