M$ is typical for suing others over software patents, there's no doubt about that.
The one thing about FOSS is that it's designed to live on forever, not only last so long as a corporation does. M$ is just here now, but won't be in the future. They will get killed by Google, perhaps not by Android but by Chrome OS, which does NOT contain any patent-infringing components and, on top of that, is designed for the PC
, not the phone, so would not only be FOSS but would also completely be an M$-killer.