Azir or Jayce?

Depends what you like more. Azir is good for sustained damage over longer fights. Jayce is all about the long range poke and early game damage.

The other thing i'm going to tell you is Azir has a really high skill cap. Jayce is alot easier to use right away.

Azir in my opinion, He can carry much better than Jayce.

Again only my opinion, but he is really strong.