Zed is a great assassin and with the recent change to the QSS, he becomes and unstoppable monster in mid and late game. He has a very high skill cap but if mastered can be one of the greatest assassins in the game with the potential to 1v1 any champion. His strong point is his mobility, giving you the pressure to roam the map and influence side lanes which most mid laners can't do as well as Zed.
The only downfall to Zed is he can easily be dealt with in team fights by exhaust or champions such as Janna or Tahm Kench.
Flat Ad is a great way to boost your early laning phase and makes your laning extremely strong. Armour Pen scales better into the late game but i prefer going for early kills and lane dominance.
Flat AD is great to give a boost to your laning phase and csing ability. Although armour pen scales better, I think lane dominance is key with zed and this will help you achieve that.
Early game on zed is very simple, use your Q whenever it's off CD and stay a safe distance away to avoid being ganked. Your abilities have a long range so see yourself as an ad caster rather than melee in lane because one wrong move or a misuse of your W and your dead. Kill pressure is possible if you land enough poke and follow up on a W, but just be careful because if you go all in you have no escape.Make sure to pre-cast which you can do with your W, pressing E and Q before the shadow lands which will increase the chance your abilities will hit. Vs Ap matchups build this early with boots and you shouldn't have any problems vs burst mages giving you the lane advantage once again. I definitely recommend after this getting your which is a primary item for ZedVs Ad matchups simply rush your and which will ensure you can 1v1 even if they build ninja tabi.
Mid game is where you start to get dangerous. Sitting with these two items means you should be able to 1v1 anybody on the map, and you can potentially start your split push. Make sure to always itemize towards who you will be split pushing against to ensure you have an efficient split. If you're against champions such as or I recommend getting a to give you the advantage in the duel.
Late game is where Zed can be very difficult to pull off. Especially if the enemy team has stacked armour and has a disengage champion such as or . You need to get a great flank for a team fight or simply continue your split push and attempt to get the inhib or draw enough of your opponents that your team can get an objective such as baron or dragons. Make sure to look if you need a or to ensure you have the potential to 1v1 enemies that have lifesteal or if you are forced to teamfight and trade 1 for 1 with the enemy ADC who doesn't have a GA.
To conclude, is a high skillcap champion that will reap you the rewards if you put the time in to master him. With amazing damage and mobility he is a top tier assassin and fits right into the meta against lacking CC teamcomps.Thanks for reading