Yeah, I agree with Requiem_Jeer, it really depends on optimization. Druid is automatically an amazing class, even with terrible stats and poor spell selection you'll still be incredibly powerful in and out of combat. Clerics at low op fall into the healbot role too often, and blaster wizards without mailman level tricks are mediocre. But at high op wizard has endless versatility and power, and is probably the best at any level.