Jesus was God, and one with the Creator and who existed at the time of creation. He became man in every aspect but sin and conquered sin and death which is a victory for mankind as he became truly man and opened the way for mankind to attain God/heaven.

Buddha was a man who sought enlightenment as a human. He was among the greatest humanitarians, but then there are a lot of humanitarians in history. Only being a great humanitarian does not lead to the realisation of God. They are very close to the beatific vision, but miss it as they seek enlightenment only up to the human level. For eg. Bill Gates the richest person on the earth is also a great humanitarian, but unfortunately he is an atheist like Buddha.