Nidalee or Heimerdinger?

I don't play much of the donger but he does have a solid laning phase thanks to the turrets. Same for team fights thanks to the ult but he's very position centric. Position of himself and his turrets to be exact. He falls into the age old stationary mid area.

Nid on the other hand isn't what I'd call a good midlaner anymore. I say that mainly because much of the damage that she has now scales better in a hybrid sort of manor and not straight ap. Granted straight ap will still get the job done if you want a full potential Nid you'd want to build her hybrid bruiser and possibly take her top lane. She's a mix between bruiser and assasin now.

Personally I like Nid a lot more than the donger but, as you can tell by my icon, I like assasins. So if you're icon is anything to go by I say grab Nidalee.

Heimer is a pusher/ siege kinda guy. very strong near his turrets. kinda useless if they are on cooldown and away from team fights. Very simple to play.

Nid is not position dependent. can chase/ escape and be hybrid built. She can support without items and summoner spells. she can also ward the mid bushes with her traps.

each game you should try to counter pick the most likely to be mid opponent.