FF, mobis, BORK if I am fed, just the cutlass if not, then I get at least a giants belt, then finish bork or tanky from there. I go q, then e if I can level 2 gank somewhere or w if not, then the third skill, then max E first for the cdr(getting two dashes in a fight is massive when ganking or skirmishing), q then w. Best thing about Xin is how opportunistic he is. He jungles at max hp and I just use q and w to clear camps so mana isn't bad, you can gank at 2 easily when people don't expect it, you brawl like a mother, and your single target is great so when you invade you just plow through their jungle taking the big creeps in like 10 seconds.
Best thing about him is if you have a gank opportunity and you're willing to burn flash it's almost guaranteed first blood. I got a riven 3 kills in like the first eight minutes last night and the game was completely over. With the FF junglers it's also like old Nasus jungle because as soon as you get wriggles you grab a scanner and a pink and ninja dragon pretty easily. I tried to play Zac last night against a Nocturne and it was completely laughable. You can't skirmish 2v2, you can't clear as fast, you can't invade. You are just completely outclassed. And I say that as someone who has a 60% winrate on jungle Zac this season and is my most played champion.