OHMYGAWD!!! It's a better Healing Salve! That being said, it's a better Healing Salve. It's not that great. Why? Well, preventing damage to yourself is just like gaining life so why don't you just gain life instead? Play Cathedral Sanctifier instead and that way you can gain life and have a blocker for later on! Preventing damage to a creature is useful, but in the long run it won't do much. If it's preventing damage from a spell, why not just counter it? If it's from a creature, you've just delayed the inevitable for 1 turn. It's just not worth it.
Pros: Improved Healing Salve
Cons: Just an improved Healing Salve