Buddhism and the East
Buddhism is a religion of complete purity and sacrifice. There was no temptation
to be forgiven for, the disciples were supposed to be ascetic. This is different the views of the other Eastern religions, and the point of Buddhism contrasts Hinduism, Taoism and Confucianism. However, some similarities in opinion might be evident.
Buddhism looks down upon Hinduism. These two religions differ the most in structure and belief. The Hindus borrowed ideas from Buddha, though Buddhists did not return the favor. The backbone of the Buddhist culture defies Hinduism, for moral temptation. Hindus could experience pleasure first, as a teaching tool. Their Karma relied on how much sin and pleasure they enjoyed during a life. Buddhism has no part in pleasure. It is based on being ascetic from the beginning and pure without any previous sin.
Another major difference was that Hindus found a way to express their religion. Even though Buddha felt his was so great, there was no verbal expression or literary prose that could describe or teach it. To Buddha, Hinduism appears to be second rate, in that the disciples act out in pleasure to achieve a holy soul. This was irrational in the eyes of Buddhism. Hinduism also had ways to show faith, either through words or exercise. This was not a trait of Buddhism.
Buddhism really has no dealings with Confucianism. Confucianism was more of a system of rules, and a peacekeeping entity, than a religion. Therefore, Buddhism would have little, if none, opinions on Confucianism. Viewing it as a religion, would make it appear different, for it defied the same Buddhist theories that Hinduism did: clear explanation of the religion.
Buddhism had little in common with Confucianism. The two different faiths were apples and oranges. They headed in different directions, and served different purposes. Buddhism was more of a spiritual aid, as Confucianism was more social. In my opinion, I really don't think Buddha had a right or a reason to comment on this religion at all, for it was very foreign, unlike Hinduism, which was very similar.
Taoism most resembles the Buddhist faith. In the Tao religion, there was also a belief that a religion could not be expressed through any words or exercises. Therefore, Buddha must have embraced this religion. Taoism was also centered on inner peace, nature and spirituality. Most of the religious goals in Taoism paralleled the Buddhist faith, therefore, I imagine Buddha looked strongly upon the Toa faith.