Shkarn

I recently heard people talking about this combination, but I'm having a hard time seeing it overly strong assuming the priest gets focused. Does anyone have experience with this setup and what the strengths and weaknesses are? I haven't done any serious arena since mid-Season 2, so I'm a bit out of touch with the current 3s teams. The biggest pro I can see is there's a massive amount of damage, but it seems really susceptible to high-melee teams and high-CC teams. What are your thoughts and comments?