I really wish people would put their "Hollywood knowledge" of cloning aside before they start writing on the subject.
Cloning a human has nothing to do with duplicating a nice or good person. It is understood that personality develops as a person grows, and is extremely susceptible to the "butterfly effect" of change, such that even two clones created at the same time and raised together would be different people at heart. The people who write about that are actually thinking about "copying" a human, not "cloning" one. These are two completely different concepts which need to be distinguished.
Cloning has its merits and is quite possible. Copying, that is to say making an exact copy of an adult, is currently impossible and probably will be for quite some time. There is nothing wrong with cloning. Nature does it all the time, in the form of identical twins. They're simply clones at origination, rather than clones of something already living.
People say Dolly the sheep is a negative example of cloning?
What happened to Dolly the sheep is important. It was not a failed experiment, it was only that. An experiment. Anyone who looks at that and says it failed, does not understand science. Its not a matter of success or failure, but what you learn on the way. Dolly the sheep had a lifespan shorter than was expected. The scientists found that Dolly's DNA was about the same age as its parent even though it was just "born," and so its lifespan was in fact normal, minus the years that its parent had already lived. Is this a failure? Absolutely not. In fact, it is monumental. What it shows is that as our genes are the cause of aging. If those scientists continue their experiments with cloning and learn how to give a clone the full lifespan expected of a true-born creature, they will have in fact learned how to stop or reverse the aging process.
Human cloning isn't too close for comfort, it is too slow for our benefit. It is the most benevolent field of research we have available, yet people are balking at it and creating negative propaganda and slowing its progress. Through human cloning, we will learn more about ourselves than ever before. Making clones isn't the point. Worrying about clones is like seeing it as a success or failure experiment. The importance of cloning is the knowledge we gain in the process, and the benefits we can reap from that knowledge.