I would rather see MOS on PS3 than any other platform. Here are a few reason:
-Cheap
-Very powerfull processor
-Will be available for many years to come
-Many people already owns it
Only thing bothering is the fact that accelerated GFX are disabled when using other OS with PS3. This could be over come by writing an acceleration driver for the SPEs, but that kind of think would eat up a lot of development resources.