PROS

Range,
Vayne is not only a great AD carry, but a Range AD carry!
Solid early game,
Vayne is one of the harder hitting champs early game!
Very mobile,
Vayne's passive combined with her ultimate gives her very nice speed when chasing down champions!
Tumble,
Its almost like a mini flash, with a 2 sec cd!
Amazing ganker,
Vayne excels extremely well at getting around the field and ganking enemy champions!
Chasing pro,
Vayne is by far one of the best chasers in the game!
Damage,
Vayne's damage is so strong that Riot had to nerf her very early on after her release, and guess what? She still is strong as hell!


CONS

Squishy,
Vayne is not a very durable champion and because of this we need to fix this weakness with items and runes.
Focused,
Vayne is so good if played right, that without a doubt will always be targeted first and focused.
Mana dependent,
After the recent nerfs we find Vayne to be much more dependent on mana, and you have to use your abilities wisely so that your not running on OOM.

Flash: Where did she go? Don't you hate that, your about to finish off a champion, then Flash they are gone and you get so pissed! Well this spell can also be used in retrospect, your in a bush waiting for that enemy champion, then you flash on top of him before he can even realize whats happening he is dead! mwhahaha Flash is FTW, Take it don't ask questions!


Exhaust: Exhaust is one of my other most favorite summoner spells, I can't tell you how many times I have scored First Blood and early game kills with this one spell. It is also an excellent tool for chasing, where you going bro! *popped exhaust* U Dead!

Night Hunter: One of my personal favorite passives in the game, Vayne gains 40 movement speed when moving towards an enemy champion! Are you kidding me? You mean that I get to run faster just because I am moving towards you! Epic! Now no more cowardly champions running away, you cant get away from me this time!!


Tumble: Tumble is the bread and butter of your champion, you will use this ability 95% of the time! Whats so neat about this ability is that its like a mini flash, she tumbles around the map, and when she comes out of her roll, her damage is increased drastically! Combine this with Silver Bolts, and lets say a Sheen or a Trinity Force, and you have yourself a deadly little move! So many things all packed down into one ability! This is my personal all time favorite ability!


Silver Bolts: I keep seeing silver rings forming around any enemy I shoot at, WTF, why is it doing that? O duh its Silver Bolts! Silver Bolts isn't just a neat little silvery metal ring graphic but it actually is how Vayne pushes big DPS. on every third consecutive attack or ability Vayne will deal bonus true damage equal to a percentage of the enemy's max hp! This means that every third hit Vayne will hit like a mad man that lost his crack pipe!


Condemn: Condemn gives Vayne some well needed utility, besides the boring, right click shoot tactic. What Condemn does is it knocks back the enemy champion dealing damage, but the neat thing is, if they hit a wall or any terrain they get instantly stunned for 1.5 seconds. OMG Vayne has a stun too!! What doesn't she have!!


Final Hour: Final Hour, I could go on for hours talking about how amazing this ability is! So let me try to contain myself and explain what it does, First off the most noticeable thing it does is quadruples your bonus movement speed you get from Night Hunter. What that basically means is instead of 40 movement speed you gain 160! OMGWTF! yea your telling me, This nifty little ultimate makes you the best damn chaser in the game hands down! But that's not all folks, we have more to go. Aside from the bonus movement speed, this ultimate also buffs up your Attack Damage significantly, so you hit so much harder! But what the neatest thing about this ultimate is that you get to stealth too! After every tumble you stealth for 1.5 seconds! ARE YOU KIDDING ME!!! Vayne gets a stealth too!!!! WOW BEST DAMN ULTIMATE IN THE GAME!!