Superman is the greatest superhero of all time and the basis for every comic book superhero since (Thats why they call them superheroes). That being said, he's incredibly difficult to write. A quote from Grant Morrison: "It seems to go wrong when the writers feel overwhelmed by the character's 'powers' and assume that because he's Superman he has no recognizably human weaknesses and is therefore somehow bland and uninteresting. He's only super-powerful physically, however, and, as I say, his heart is as vulnerable as anyone else's, which makes for great stories."
Most writers are intimidated by Superman and look at him the same way most of you do. He's nearly invincible, so how the hell do you pose a real challenge to him? You hurt him emotionally. Have you ever wondered why Superman, with all his powers and strength, has been constantly challenged and humiliated by a balding old man? Luthor understand better than any other villain how to really hurt Superman. Most writers don't get this idea though, so they write Superman all wrong. Another Morrison quote (You should know that I had no interest in All-Star Superman until I read Morrison's point of view on Superman and realized how great he really is): "You've got to make Superman about a few things. It's got to be about big emotions and big human feelings like death and loss and bereavement and grief and joy. Then you weave these weird sci-fi stories around those themes. I think those are the best Superman stories-the ones about human feelings but on a huge, cosmic, ridiculous, superhero canvas."
Superman can fully live up to his reputation in the right hands. If you don't like Superman, than you've probably just been reading the wrong stories.