ranged: they analy penetrate you early game
melee: u penetrate them early game
for both, ur late game should be better with good box placements!

For this build to work, you need to have pure ad reds, to cs properly.. you are free to do whatever suits you best with quints, blues and yellows. i recommend some CDR.

Early, Almost ALWAYS get Hextech Revolveron the first back. people underestimate the burst this item provides a ton, it will help you in getting first blood. Ofcourse sometimes you would back with about 500g or less. in that case, get a Control ward and another doran's ringif you are using your E for harass/cs. or get boots if you find yourself going to roam. After the hextech Revolver, get a Tiamat. this will help you push and cs. and it will also provide a little burst with the active. then finish off the hextech Gunblade. by now,you have enough dmg to burst any squishy. and you would have to choose either to build for splitting or build for more burst! it's all the same build but the order is different:
for split-build:,,,,.

And you could probably guess by now what's the dmg build.. (IE, DEATH CAP, STATIKK...)
A real nasty build is replacing the zhonya's with a ludens echo. combined with the infinity edge your Q would do a ton of burst without even considering the statikk shiv and gunblade!