I've had the model for years, even before I was going to build a Nurgle Army.
I love the Command Ability the Harbinger of Decay gives the army. If this ability is used, a unit within 7" of the Herald of Decay may ignore wounds AND mortal wounds on a 5+ on a d6. This makes an army full of tough models even tougher! The Harbinger himself carries a Soulbound Shield (slung on his back) that allows him to ignore wounds caused by spells on a 4+ on a d6.