As the title says, post the champion you think is the hardest to play, and the single champion you are doing best with at the moment.
For me i think Orianna is still the one that requires most skill to master, some said Syndra was harder, but i seem to do fine with her with little training.
I seem to always do really well when i play Varus, be it him being good in teamfights or me fitting his playstyle...