I adore Cilan, even if he does look like a zombie in the games <3 I love all of the Striaton Trio since they look so smart and perky and offer a very interesting battle with the way they choose who you'll fight, so they're definitely my favourite gym overall - it's just a matter of choosing which leader is the best! Chili is great and very cute but he's a bit... quirky, for me, so he's certainly not number one. Then there's Cress who's all calm and cool, but I just can't get over how ridiculous Panpour is so I dislike him for that reason alone. Therefore, Cilan must be our winner! He's a very interesting trainer with a great choice of Pokémon (despite only having two!) and I can relate to his Grass type training decision, so he's certainly my favourite gym leader in Unova.