So is Zac fun??

I would say "You should wait until you have played a champion before buying them". I could answer like he is a fun champion with a great, amiable personality or something but that says nothing about whether or not you find his playstyle fun. You could spend 6300IP and get someone you don't like at all and that would suck

I've been running Zac and Rek'Sai as my go to junglers. Zac is one of the more fun characters to jungle with. Fast early clear, decent sustain, unique ganking style (jump into lane from afar); doesn't really fall off. Zac is highly underrated in my opinion.

I am running attack speed marks, armor quints, scaling hp seals, and cooldown reduction glyphs; 9-21-0 masteries.

You want to max E, the slingshot, first to increase the jump distance. You could put an extra point in W at 4 for clear speed though (still max E by 9)

zac is actually ridiculously fun to play. he's just not very strong when compared to other tank junglers.

Well he is my go to tank jungler and i love him to bits.

Hes weaker than say, sej or gragas but nothing is more fun than sling shotting in and ulting the enemy into my laner.

And if you can pick up his goo chunks when your farming he has some great sustain.