Isaac's. Only because he's sooooooo slippery and sometimes the debris will get in the way of your kill. And lastly, Isaac is just as slow as the ragdoll opponents. I've gotten 0 kills with it before, but I'm not gonna bash it just for that.
Isaac's is pretty awful at the moment.
isaac's level 3 isnt too bad once u get used to it. the first couple of times i used it, i found myself struggling to get kills because of the way u have to aim the joystick to shoot people. to this day, im still not great at it, but im definitely alot better at his level 3 than i was before