Well, counter building is something in this game, if you dont do it you dont win, simple. And i think this is horrible champion design. Getting a Zhonya/QSS means Zed cant do his job, and since this two items are GOOD on his targets (APC and ADC) then you dont even punish them with sub-bar items.
Honeslty hating Zed is kinda dumb, the fact it's so easy to counter build it's kinda retarded when you bitch about him killing you, especially as an ADC, since the item cost 1250 G or something, and gives you MR and a good active.
I do hate, however, that he can 100-0 WITHOUT his ult tick. Just by ulting and using the dmg from the 3 shadows + Botrk+ Hydra+ AA he can kill you.... Granted that's a long combo, but still, I think he is the only assasin that can 100-0 somone without his ult.
EDIT: Oh, and the fact that the DMG from the ult IGNORES resistance, meaning you have to save your def skill for the tick not the dmg, which I think is kinda bullshit, and it's hidden iformation.
I found out about this while playing Yi against him, meditated his full combo and barely did dmg to me, then once I left meditation the tick went of and took ALL my hp, only needing a single AA to finish me off.
That's really bullshit.