And ik think its better to rush ER becuase of the cdr :)

The armor pen build is good agains non-tanks because you are very close to true damage against them. And against tanks it doesnt help that much becuase they will build armor. My conclusion is that armor pen is better against non-tanks and critt is better against tanks. I hope this will help you with playing Jhin and other adc champs.
Sorry for my late reaction ^^

I think its the armor pen build, but don't quote me on it. Imaqtpie uses the armor pen build, so I'm just going off of that.

thanks man XD