Once you have spirit visage and the ionian boots, your transfusion will have a 2 second cd at lvl 9. This is great early game because you won't need health pots since you can just feed off minions without worrying about wasting a cd. It's amazing for harrassing all times during the game. Once you have more ap end game, you'll easily beat anyone 1 v 1 because you can just keep transfusing them and gain back your health while they are still losing it. Not to mention the squishies will bend beneath your wrath endgame.