It's being reported on another forum that M Life Platinum members can now get a free Royal Caribbean 3, 4, or 5 night cruise in an ocean view cabin (no balcony). It's limited to 4 ships: Enchantment, Liberty, Jewel, and Brilliance. You must book prior to 9/30/13 and sail before the end of this year. It excludes holiday sailings. You are responsible for taxes and gratuities. Apparently this will be an annual perk.
This person didn't know what perks the other levels might be eligible for.