The Buddhist sutras limited to the form, time and the space, the Advaitic truth is beyond the form,time and space.+

Gate gate para gate parasamgate bodhi svaha.

The heart sutra is a great sutra.  Yes,  it takes us to the inner realm but all the Buddhist sutras are limited to form, time, and space, the Advaitic truth is beyond the form, time, and space.  Since the self is not the form self is formless. All the skandas are in the physical realm (Form, feeling, perception, mental formation, and consciousness).   

The Self has not limited the physicality, but it pervades in everything and everywhere in all the three states.  Thus, the heart sutra yields only half-truths.  

The Buddhist scriptures were completely distorted by the time of Sage Sankara. Sage Sankara had to criticize the Buddhist literature prevailing then as the Buddhists themselves were confused as to what Shunyata is. Vasubandhu and his disciple Dignaga (the latter lived about a couple of centuries before  Sage Sankara) could not retain the original teachings of Lord Buddha. At first, Vasubandhu did not agree with his half-brother Asanga and wrote one book on Abhidharma and later on, he went to the side of Asanga and wrote a second book, where? he opposed his own earlier views on Abhidharma. Sage Sankara had to criticize the Buddhist knowledge? and literature of his time as he wanted to bring to us back the Pure Vedantic knowledge through his work on the Prasthanatraya. That is why there is a reference to the writing of Dharmakirti in Sutrabashya.

Buddhism has not proved the truth of Non-duality.  There is no doubt Buddha pointed out the unreality of the world. He told people they were foolish to cling to it. But he stopped there. He came nearest to Advaita in speech but not to Advaita fully.

The distinction between Sage Sankara's Advaita and Vijnanavadin Buddhism are that the former is mentalism i.e. mind is the real, whereas the latter is idealism, i.e. ideas are real. We follow the former.

Buddhism did not graduate its teaching to suit people of varying grades; hence its failure to affect society in Asia.

Bhagavan Buddha's teachings that all life is misery belong to the relative standpoint only. For you cannot form any idea of misery without contrasting it with its opposite, happiness. The two will always go together. 

Bhagavan Buddha taught the goal of cessation of misery, i.e. peace, but took care not to discuss the ultimate standpoint for then he would have had to go above the heads of the people and tell them that misery itself was only an idea, that peace even was an idea (for it contrasted with peacelessness). That the doctrine he gave out was a limited one, is evident because he inculcated compassion. Why should a Buddhist sage practice pity? There is no reason for it.

Advaita is the next step higher than Buddhism because it gives the missing reason, viz. unity, non-difference from others, and because it explains that it used the concept of removing the sufferings of others, of lifting them up to happiness, only as we use one thorn to pick out another, afterward throw both away. Similarly,  Advaita discards both concepts of misery and happiness in the ultimate standpoint of non-duality, which is indescribable.

Buddhists say that a thing exists only for a moment, and if that thing has still got some of the substance from which it was produced, how then can they deny that its cause is continuing in the effect; hence its existence is more than a moment. Vedanta is concerned with whether it is one and the same thing which has come into being or has it come out of nothing.

There is another aspect also, Vishnu Purana also says that Lord Buddha created confusion. In Sarnath, he first taught about the Moral code which is basic. He talked about Anatma. Then? two decades later he taught the concept of Shunyata and? the tenets of Mahayana Buddhism.? In spite of Nagarjuna's telling that Shunyata is not Nihilism and that Parajanaparamita also mentioning about the Shunyata after one leaves? the five? skandhas, there are and there will always be people who will go on calling Buddha's philosophy as Nihilism. About the origin of the? Tantric Buddhism also? there are controversies.

Buddha as a constructive worker committed an error in failing to give the masses a religion, something tangible they could grasp, something materialistic, if symbolic that their limited intellect could take hold of, in addition to his ethics and philosophy. Here Sage Sankara was wiser and gave the religion; such as Bhakti, worship, etc.--to the ignorant masses, as well as wisdom to those of higher intellect.

The Advaita Sage Sankara' gave religious, ritual, or dogmatic instruction to the populace but pure philosophy only to the few who could rise to it. Hence, the interpretation of his writings by commentators is often confusing because they mix up the two viewpoints. Thus, they may assert that ritual is a means of realizing Brahman, which is absurd. 

The most valuable contribution of  Sage Sankar is that he gained general consciousness on the issue that the authoritative explanation of Upanishads, Gita, and Brahma Sutra was the final say in a matter of religion. Anything that goes contrary to the trio is not authentic. He also made a clear distinction between Vedas and Upanishads in his commentary on Gita. He stated that the Karma Kand of the Vedas deals with the injunctions relating to the performance of duties and actions. These are for ordinary householders.

  

The path of religion,  the path of yoga, and the path of wisdom were intended for different classes of people. The wisdom is for the advanced seekers of truth. It deals with the nature of the ultimate Truth and Reality. It is meant for superior aspirants who have an inner urge to know the truth and it is not for those who are immersed in earthly desires.

Sage Sankara’s whole teaching can be summed up into one sentence, ‘There is nothing else, but Brahma  He says that the Absolute Existence, Absolute Knowledge and Absolute Bliss is Real. The universe is not real. He says that Brahma and Atman are one. The ultimate and the Absolute Truth is the Self, which is one though appearing as many in different individuals. The individual has no reality. Only the Self is real; the rest, mental and physical are but passing appearances.

In fact, Sage  Sankara states a paradox- the world is and is not. It is neither real nor unreal. It leads us to recognize the existence of Maya. He thinks that the world is illusory from one perspective and from the second it is nothing but Brahma  Itself in manifestation. This apparent world is Maya and has its basis in Brahman, the Eternal. It looks real. It has names and forms and actually, it is not real In the light of true knowledge, it disappears and Self-alone shines as real. However,   Sage  Sankara's  Maya vada has not been accepted by many preachers and philosophers.

When Sage Sankara says clearly, the universe is not real. He says that Brahman and Atman are one. The ultimate and the Absolute Truth is the Self, which is one though appearing as many in different individuals. The individual has no reality. Only the Self is Real; the rest, mental and physical are but passing appearances, then it indicates the form (waking or duality or mind) is unreal the formless witness is real (Soul).  Therefore, only Atman is real because there is no second thing other than Atman.

He also clearly mentions that:~

The path of religion, the theory of karma, the path of yoga, and the path of wisdom were intended for different classes of people. The wisdom is for the advanced seekers of truth. It deals with the nature of the ultimate Truth and Reality. It is meant for superior aspirants who have an inner urge to know the truth and it is not for those who are immersed in earthly desires.

Thus, we have to know the fact that Buddha, Sage Goudpada, and Sage  Sankara are not only reformers but also the greatest scientists. Since their original thesis on the path of wisdom has been lost in the labyrinths of philosophy and mutilated by pundits and priestcraft, it becomes very difficult to understand and assimilate the wisdom expounded by the great masters. In addition, the conservativeness of the orthodox scholars will not allow any research other than playing with the words, which suits the mass mindset, because of their egocentric outlook.

All the add-ons have to be discarded, in order to understand and assimilate the real fragrance of the wisdom expounded by the great sages of Advaita, but it is a hurricane task.  Thus, it is no use going through all the scriptures, when there is a direct path to non-dual truth.  The same time and effort can be used to reach the non-dual destination, in lesser time and effort.:~Santthosh Kumaar