Originally Posted by Z The Slayer
A lot of it is time. Yes, it's true that he gets close to gank, but Eve has a short grace period of how long she has to be within vision range to be seen. In the demonstration with TF, there is a long amount of time of just doing nothing, so the vision range feels too far, but in ganks, Eve moves quickly, so that by the time the grace period is over, she's in your face.
As for Armor Pen, it is much more efficient to get a Last Whisper, and ignore any flat armor penetration, since % penetration is the last piece in calculation.
oh so its like hecarim, they move so fast it wont mater if they see you. thinking about it this way i can appreciate this passive a lot more.
i usually get a last whisper anyway so i can so how ad marks are better. i hear they give you a better early game too. now i just got to buy them....