I have a friend who was absolutely devastated that they took out Mewtwo in Brawl. He absolutely swears that his neutral air and teleport mindgames make him invincible.
Edit: Salluz, I'm going to talk to you like a friend and give you some honest advice: for your own sake, don't post as if you are a veteran or expert at something. Questions like "what's so great about Dedede" (answered by Derrit) and "Is Crazy Hand in Brawl" (the answer is yes; you'll find out later that he is being controlled by an even more powerful being) are fine, and people will gladly give you what you need. But if you try to give tips to the "n00bs," you just sound arrogant and end up making a fool of yourself, because for the most part your advice is redundant at best and plain wrong at worst. As the cliche goes, if people want your advice, they will ask for it.