We have heard of great Mahans chanting the Rama Nama or the Krishna Nama towards attaining God-Realization. Are there other Mahans besides Chaitanya Mahaprabhu who have chanted the Maha Mantra to attain the Lord? Moreover I have read that a Sadhak should stick to one name and form. The Mahamantra has both Rama and Krishna's names. So to avoid the mind from wavering can I contemplate on my Guru while chanting the Maha Mantra?
Sri Sri Muralidhara Swamiji:
The beauty and power of the Divine Name is that it completely takes over. All you need to do is chant. when you chant do not bother whether your mind wavers or not. Nama will take care of that.
Though there maybe so many names and mantras, this mantra is specifically prescribed by the Upanishad for this age (Kali Santarana Upanishad). Chaitanya Mahaprabhu, Swami Sivananda, Swami Abhedananda, numerous sadhus in Vrindavan, advocate this mantra as the simplest solution in this Yuga.