From my personal sight as a gamer, I think Microsoft should rather buy Remedy because they make absloute unique games in an great quality.
But from the sight of Microsoft Harmonix would be a better deal, Harmonix make gerat games many peopele like there Games. There Games bring a lot of many, they would bring more money then the games of Remedy ( this is sad because i love the games from Remedy)and Harmonix fit perfekt for Kinect.