Both are pretty decent, but I'd say Kled is a lot stronger. For Yorick, you're extremely weak to bullying and pretty much just have to try to scale up, taking early trades by throwing your E on the enemy while you have minions up to launch them at the enemy whenever you can, but you certainly don't want to do the work yourself. Kled is the exact opposite. Damn it, Skaarl, get in there so I can kick some ass! As Kled, your goal is to fight and kill things as much as possible because you can kill them. You're an early game powerhouse that can snowball a game out of control solo with your damage and roaming capabilities, while simultaneously being unkillably tanky. Did I mention that you can get back literally your entire health bar by hitting an enemy 5 times, 4 of which come back from your W, which is an attack speed steroid?
CHAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAARGE
Yorick is more flexible, able to be played both in top and jungle if you know what you're doing with him, and probably the best split pusher in the game.