What do you think of Zac?

I've always had a slight interest in Zac, but when he became free this week, I absolutely loved him. I've won nearly all the matches I've played with him both jungling and playing top lane, and I also like his overall concept/character. His slingshot ability really makes it fun, at least for me.

I am aware, however, that he is not played that much. I was wondering how he does later in ranked matches, since I've been told that you can do well with pretty much any champion when you're still not ranked. Is he really easy to shut down? Or do people not play him because he's been nerfed too much? Is he just not easy for people to use? I'd like to keep using Zac, but I want to know why people don't seem particularly attracted to him.

Lastly, Zac himself says "I need a suit." Riot should give Zac a skin of him wearing a suit :D