Yea this item is insaley good. I main Wukong, all I have to do is rush this item, screw vamp scepter for a Crystaline flask, and just time my EQWR + Ignite right and its insta kill. If everyone on team is evenly matched in lanes against opposing team, I usually get first blood and become this unstoppable force. Just have the support heal/shield me and the enemy has no armor. If I don't manage to get the kills atleast everyone on opposing team has no armor so my adc just has a field day.
Edit: with the re-introduction of block, I kinda get the feeling that they wanted block to counter armor pen. Ninja Tabi hence becomes more useful, along with dorans shield, atleast for a short while in early game.