Shaco is annoying, he's highly capable of jungling and ganking as well as escaping enemy ganks. He can also persistently harass opponents with that irritating little toy thing of his that shoots stuff and causes fear. His ult is tactically useful, it could be employed to tank turrets or to confuse enemies in team fights as well as escaping dangerous situations. I jungled Jax recently against a jungling Shaco and found that invading the enemy jungle early to harass him and steal his buffs is quite useful as he's almost useless alone without his ult.
Best analysis. Ever.