Pro's & Cons
Pro's
-Able to 1vs1 almost everything
-Can't be kited at all
-Good sustain
-Very good team fight initiation
-The enemy team WILL have to focus you or else they're going to be disabled or dead
Con's
-Very bad escaper
-Can't protect his team as good as most other tanks
Playstyle
In the laning phase you want to farm as much as possible and deny your opponent farm at the same time, by either zoning or killing him if possible. With Xin's good sustain, high early game burst and zoning ability this is very simple against most enemies you'll face. The success of this strategy depends on your ability to "trade damage" with your opponent, meaning you can take the damage of your lane opponent and return an equal or even greater amount. This will enable you to farm your lane and maybe even zone your opponent (forcing him to give up last hits because they can't trade damage with you) or kill him. With your distance closer 
Audacious Charge you can even zone some ranged champions! Xin is also very good in clearing the jungle and dragons, so make sure to utilize this if you are dominating your lane.
In teamfights, you will take the role of an offtank/initiator. It means you want to be the first or the second person on your team, to dive into the enemy team when your own team is prepared for a big fight. You will go for their squishy carries, knock all their teammates who are protecting them away with your ultimate 
Crescent Sweep, and continue to focus their carries until either they are dead or you are dead. You are quite tanky so if they killed you, they must have focused you or used some major skills on you. This should allow your team to eliminate the rest of them and win the teamfight.
Skills
Challange
Xin's new passive is very good; basically it lowers the armor of whatever target he is attacking. It enables us to sacrifice some armor pen runes for attack speed runes.
Three Talon Strike
It now applies cooldown reductions on ALL SKILLS(!) whenever he hits one of the three attacks of this skill, so use this after you activated your other skills. It also provides excellent burst and and a good knock up. I believe this skill should be maxed first regardless what role you intend to have Xin fill. Every time you level this skill, it's cooldown will decrease and this skill decreases the cooldowns of all skills (which basically means you can almost spam your ultimate). It also provides very nice burst damage for low mana cost, which makes us possible to trade damage with almost every other champion you will face. This skill also resets you auto-attack timer, so using it immediately after a normal auto attack greatly improves your damage early game.
Battle Cry
This skill provides you sustain with a good passive effect which works very similar to lifesteal and can be activated for an increase in attackspeed for 5 seconds. This skill was nerfed hard in the rework. It's the cost of the improved other skills. It used to give him cooldown reduction on all skills per attack (which was transferred to Three Talon Strike) and a permanent attack speed bonus in addition to the activated effect, which was very nice for jungling. But, we are not jungling! When laning solo top, it's more important to be able to trade damage, which the active 5 seconds of this skill does well enough. I put a skill in this on level 1, because you shouldn't commit to killing your opponent at lvl 1 and this will give you sustain while last hitting.
Audacious Charge
This skills is a distance closer with a slow and a bit of damage. How you use this skill greatly determines your success. It's a distance closer, so you should only use it to actually close a distance you can't close otherwise. I usually don't use this until the enemy is committed to running away, unless you really need to be on an enemy FAST (usually a carry in a teamfight or when you are ganking). It's highly prefered to use 
Ghost to engage an enemy and use Audacious Charge after they flashed away. This skill can also be used as an escape by targeting an enemy minion on your escape route. You can even charge though walls if a target is visible on the other side. I use this skill mainly as a distance closer and max it last. Although the increased slow when you level this skill is very nice, it doesn't help you trade damage. Against ranged enemies this skill must be maxed earlier.
Crescent Sweep
This skill has become awesome with the rework. It does good Area of Effect (AoE) damage, buffs your defenses and now knocks everyone back except the target you last attacked! It means you when you charged that ad carry, you will knock all those pesky supports and tanks protecting them away, so you can finish you job of killing the bastard. It really messes up the enemy team's positioning. Also note that this ultimate can be used to knock an enemy ganker away or disable a channeled ult. It should also be used when you are towerdiving, because it increases your armor. Because we are also spamming Three Talon Strike with it's cooldown effect, we can almost spam this Crescent Sweep!
Masteries
I go 21/09/0 because Xin still must do a lot damage for early lane dominance and late game carry-killing. My items are quite tanky so these masteries will help greatly. Alternatively you could go 09/21/0 which should work fine if you are more focused on sustained farm instead of aggressively zoning your enemies
A note on laning
I mentioned that Xin can zone his enemies. This is how you do it;
At lvl 1: just last hit and don't commit to fights, especially when they have exhaust or ignite
At lvl 2: keep it save and prioritize on last hitting. If they seek a fight, activate Battle Cry and Three Talon Strike and run away after the knock up. Continue to last hit and your sustain and health potions will heal you. You can even try to zone your opponent when they try to last hit a minion.
At lvl 3: You are pretty strong right now and can actively seek fights. Charge and TTS and commit to the fight or else run after the knock up and heal
You should be able to bully your opponent from now on but be very wary of ganks. Ward the river and try to keep at least one of your escape summoner spells off cooldown.
After your Wriggle's, you should consider pushing the lane in order to be at full hp at all times. Not even Olaf can compete with your sustain!
At lvl 6 you are better protected against ganks with your ulti Crescent Sweep, so you can play even more aggressive
Summary
The new Xin is a solid top laner and very annoying to the enemy squishies. We utilize his strong 1vs1 ability and negate his weak escapes with summoner spells. With this build, I believe he is one of the most aggressive offtanks in the game and a very good initiator. If you like seeking fights and being in the middle of them, this is a build for you.
Build Guide
Discussion (5)
Xin Zhao got a rework. The biggest changes include an improved ultimate 
Cloth Armor + 
Health Potion are your typical starting items when you lane vs an AD Champion. Be sure to pick 
Boots of Speed + 
Wriggle's Lantern Together with the passive effect of 
Mercury's Treads Xin hates CC, and this reduces them. Against hard lanes you might want to build 
Ninja Tabi instead.
Phage Some HP and Damage is nice but the slow is great. With your attack speed boost and slow from your skills it almost always proc
Heart of Gold HP is never bad and we want to build 
Randuin's Omen so it's good to build this fast since it gives you gold
Trinity Force Movementspeed, Attackspeed, Critical Strike and extra damage after skills; it's all good for Xin. It's expensive and when teamfights start before your complete it, it might be a good idea to build a 
Chain Vest.
Banshee's Veil or 
Force of Nature instead.
Warmog's Armor This gives you all the HP you need and together with your resistances a stupid target to focus, allowing you to rape the enemy carries. As with most last items, you should be really flexible with it; build what you need.
Greater Mark of Attack Speed Attack speed will let you hit those 
Greater Seal of Armor Minions and most solo top enemies deal normal damage and these seals protects you. They are absolutely mandatory against these types of enemies
Greater Glyph of Magic Resist I use these for similar reasons as the armor seals, although this type of damage is less common in the solo top lane. Vs AP champs these are mandatory. I figure the 
Greater Glyph of Scaling Magic Resist are probably better and attack speed Glyphs in certain cases too, but I don't have them
Exhaust or 
Ignite if you fear you can't 1vs1 your opponent without it
Teleport A great spell to get back to your lane and teleport in for a gank/dragon. Xin is a natural pusher so you usually don't have to teleport back to your lane
