From Kṛṣṇaloka, the bodily effulgence of Lord Kṛṣṇa is distributed not only to the spiritual world but to the material world as well; it is covered by matter, however, in the material world. In the spiritual world there are innumerable Vaikuṇṭha planets, and on each one the Lord is the predominating Deity. A devotee can be promoted to one such Vaikuṇṭha planet to live with the Supreme Personality of Godhead.
In sārṣṭi liberation the opulence of the devotee is equal to the opulence of the Supreme Lord. Sāmīpya means to be a personal associate of the Supreme Lord. In sārūpya liberation the bodily features of the devotee are exactly like those of the Supreme Person but for two or three symptoms found exclusively on the transcendental body of the Lord. Śrīvatsa, for example, the hair on the chest of the Lord, particularly distinguishes Him from His devotees.
(Srimad Bhagavatam------3:29:13------purport).

These liberations are sārṣṭi (achieving opulences equal to those of the Lord), sārūpya (having a form the same as the Lord's), sāmīpya (living as a personal associate of the Lord) and sālokya (living on a Vaikuṇṭha planet). Devotees never accept sāyujya, however, since that is oneness with Brahman.
(Sri Caitanya Caritamrta------1:3:18-------translation).

When one associates with a pure devotee, he becomes so elevated that he does not aspire even for sārṣṭi, sārūpya, sāmīpya or sālokya, because he feels that such liberation is a kind of sense gratification. Pure devotees do not ask anything from the Lord for their personal benefit. Even if offered personal benefits, pure devotees do not accept them, because their only desire is to satisfy the Supreme Personality of Godhead by transcendental loving service. No one but the Lord Himself can teach this highest form of devotional service. Therefore, when the Lord took the place of the incarnation of Kali-yuga to spread the glories of chanting Hare Kṛṣṇa—the system of worship recommended in this age—He also distributed the process of devotional service performed on the platform of transcendental spontaneous love.
(Sri Caitanya Caritamrta------1:3:20------purport).

For a devotee, to get liberation is not very difficult. Even one who is unable to establish a relationship with Kṛṣṇa can achieve liberation by merging into the Brahman effulgence. This is called sāyujya-mukti. Vaiṣṇavas never accept sāyujya-mukti, although sometimes they accept the other forms of liberation, namely sārūpya, sālokya, sāmīpya and sārṣṭi. A pure devotee, however, does not accept any kind of mukti. He wants only to serve Kṛṣṇa in a transcendental relationship. This is the perfectional stage of spiritual life. Māyāvādī philosophers desire to merge into the existence of the Brahman effulgence, although this aspect of liberation is always neglected by devotees. Śrīla Prabodhānanda Sarasvatī Ṭhākura, describing this kind of mukti, which is called kaivalya, or becoming one with the Supreme, has said, kaivalyaṁ narakāyate: "Becoming one with the Supreme is as good as going to hell."
(Sri Caitanya Caritamrta------1:8:19------purport).

"A person who has completely surrendered unto Me and has completely given up all other activities is protected by Me personally, both in this life and in the next. In other words, I wish to help him become more and more advanced in spiritual life. Such a person is to be understood as having already achieved sārṣṭi (having equal opulences with the Supreme)." It is also confirmed in Bhagavad-gītā that as soon as a person surrenders unto the lotus feet of Kṛṣṇa, Kṛṣṇa takes charge of him and gives him a guarantee of protection from all sinful reactions. He also instructs from within, so that the devotee may very quickly make advancement toward spiritual perfection.
(Nectar of Devotion).

We do not want to enjoy such material opulences, nor do we desire to achieve the yogic perfections, nor the exalted post of Lord Brahmā. Nor do we want any of the different kinds of liberation—sārūpya, sālokya, sārṣṭi, sāmīpya or sāyujya. We are not at all attracted by any of these opulences. Our only ambition is to bear on our heads life after life the dust particles attached to the lotus feet of Lord Kṛṣṇa. The goddess of fortune also desires to keep that dust on her breasts, along with fragrant saffron. We simply desire this dust, which accumulates underneath the lotus feet of Kṛṣṇa as He travels on the land of Vṛndāvana as a cowherd boy. The gopīs especially, and also the cowherd men and the aborigine tribeswomen, always desire to become the grass and straw on the streets of Vṛndāvana, to be trampled on by the lotus feet of Kṛṣṇa. My dear Queen, we wish to remain as such life after life, without any other desire.”
(Krsna Book).