As it is well known, ISKCON (and other Vaishnavas for that matter) strongly criticize philosophy of Advaita. Srila Prabhupada himself criticized Mayavada in his various commentaries on Vaishnava scriptures-
"The Mayavadis say that the world created by maya is false, and that actually there is no living entity but only one spiritual effulgence. They further say that God is imaginary, that people think of God only because of ignorance, and that when the Supreme Absolute Truth is befooled by the external energy, maya, He becomes a jiva, or living entity. Upon hearing all these nonsensical ideas from the nondevotee, a devotee is greatly afflicted, as if his heart and soul were broken." Caitanya-caritamrta, Antya lila 2:99
But at the same time Srila Prabupada said BrahmanVada is permitted in Vedas( But non-dual moksha is impermanent unlike Vaikuntha) as evident here. which says-
Therefore they, these Brahmavādīs, these Nirākāravādī, although by austerities and penances they may rise up to the Brahman effulgence, still, they will fall down. Because we are living entities, we want varieties of enjoyment. We are not satisfied in void, in zero. That is not possible. Lecture on SB 1.2.18 -- Calcutta, September 26, 1974
He even said that the Four Kumaras followed BrahmanVada.
My question is What is the difference between Brahmanvada and Mayavada?