I use him, and I know he is strong... What is it that makes him so?

The fact that he can spam bonus ad attacks like mad because his Q and W increase attack speed and his Q does an extra 72 damage minimum at level 5, that and his passive shreds armor. So if you combine that with black cleaver, after 4 hits you have half the armor you did.

Strong steroids, strong passive, powerful kit with CC...

Reduced CD/knock up on Q, insane slow on gapcloser. At level 2 you are basically gaurenteed a kill if you are playing against a pusher.

i dont think xin is op at all. its the player who uses him

uh ridiculous base damage and on his q that scales with ad. So he can build straight tank and still do lots of dmg. he has 3 cc's, a knockup on q, a slow on e, and an aoe knockback on r. This makes him a malphite like initiator with his e + r and a tank build (as r does 15% current hp as physical dmg, and gives bonus Mres/Armor per enemy champion hit, up to 125 if all five are hit). Also, a really good AS steroid on his w mixed with good sustain (50 hp every 3 hits at rank five compared to irelia 13 X 3 = 39). Hie w + q pushes towers as fast as master yi, and BotRK is the only dmg/sustain item he'll ever need.

Keep in mind this is VERY biased as he and olaf are my main junglers and solo tops. (might learn Cho tho)

Forgot about that passive 15% arpen. build a LW and you just halved their armor :P

Q does a lot of damage and his passive reduces armor of the target he is focusing.

Fed Xin Zhao with AD items. No champions is OP or UP.

Because he can perform 3 strikes while you get off one, and he knocks you up and continually does it over and over. I like him, but just like any other Melee champ hes too easy to counter.

Xin Zhao specializes in engaging early and engaging hard. He has no disengage until level six. He will all-in you at level 2 with E and Q if he's top/mid/bot lane. Expect it. If you don't feed him early on, just build a bit to counter him and he'll fall off pretty hard, damage wise.