"According to Mayavada philosophy, this manifested world or the material world is mithya or maya, false. Their preaching principle is brahma satyam jagan mithya. According to them, only the Brahman effulgence is true, and the cosmic manifestation is illusory or false. But according to Vaisnava philosophy, this cosmic manifestation is caused by the Supreme Personality of Godhead. In the Bhagavad-gita the Lord says that He enters within this material world by one of His plenary portions, and thus the creation takes place. From the Vedas also, we can understand that this asat or temporary cosmic manifestation is also an emanation from the supreme sat or fact. From the Vedanta-sutra also it is understood that everything has emanated from the Supreme Brahman. As such, the Vaisnavas do not take this cosmic manifestation to be false. The Vaisnava philosopher sees everything in this material world in relationship with the Supreme Lord.
....Similarly, impersonalists headed by Astavakra and later on by Sankaracarya accept the impersonal Brahman effulgence as the cause of everything. According to their theory, the material manifestation is temporary and unreal, whereas the impersonal Brahman effulgence is reality. But this theory cannot be supported either, because the Lord Himself says in the Bhagavad-gita that this Brahman effulgence is resting on His personality. It is also confirmed in the Brahma-samhita that the Brahman effulgence is the personal bodily rays of Krsna. As such, impersonal Brahman cannot be the original cause of the cosmic manifestation. The original cause is the all-perfect sentient Personality of Godhead, Govinda.
The most dangerous theory of the impersonalists is that when God comes as an incarnation He accepts a material body created by the three modes of material nature. This Mayavada theory has been condemned by Lord Caitanya as most offensive. He has said that anyone who accepts the transcendental body of the Personality of Godhead to be made of this material nature commits the greatest offense at the lotus feet of Visnu."
Krsna Book, Chapter 87
"Srimad Viraraghava Acarya, in his Bhagavata-candra-candrika, describes the Vaisnava philosophy as follows. The cosmic manifestation is described as sat and asat, as cit and acit. Matter is acit, and the living force is cit, but their origin is the Supreme Personality of Godhead, in whom there is no difference between matter and spirit. According to this conception, the cosmic manifestation, consisting of both matter and spirit, is not different from the Supreme Personality of Godhead. Idam hi visvam bhagavan ivetarah: "This cosmic manifestation is also the Supreme Personality of Godhead, although it appears different from Him." In Bhagavad-gita (9.4) the Lord says:
maya tatam idam sarvam
na caham tesv avasthitah
"By Me, in My unmanifested form, this entire universe is pervaded. All beings are in Me, but I am not in them." Thus although someone may say that the Supreme Person is different from the cosmic manifestation, actually He is not. The Lord says, maya tatam idam sarvam: "In My impersonal feature I am spread throughout the world." Therefore, this world is not different from Him. The difference is a difference in names. For example, whether we speak of gold earrings, gold bangles or gold necklaces, ultimately they are all gold. In a similar way, all the different manifestations of matter and spirit are ultimately one in the Supreme Personality of Godhead. ekam evadvitiyam brahma. This is the Vedic version (Chandogya Upanisad 6.2.1). There is oneness because everything emanates from the Supreme Brahman. The example already given is that there is no difference between a golden earring and the gold mine as it is. The Vaisesika philosophers, however, because of their Mayavada conception, create differences. They say, brahma satyam jagan mithya: "The Absolute Truth is real, and the cosmic manifestation is false." But why should the jagat be considered mithya? The jagat is an emanation from Brahman. Therefore the jagat is also truth."
Srimad-Bhagavatam 8:12:8 Purport
Bhaktivedanta Book Trust. HDG A.C. Bhaktivedanta Swami Srila Prabhupada.