Hare Krishna,

I think this translation of "Sri Bhakti Chandrika", 7th Patala, lists the effects of chanting the maha-mantra quite nicely and concisely:

"This maha-mantra is endowed with thirty-two syllables and can destroy all sins. Just as fire destroys, this maha-mantra can destroy all evil habits and bestow dharma (duty or religious duty according to one's qualities and position, one of the four goals of human life), artha (economic development, one of the four goals of human life), kama (material enjoyment, one of the four goals of human life) and moksha(liberation, one of the four goals of human life). It's beautiful form is capable of stealing all of one's foolish, ignorant mentality,and it is the giver of suddha-sattvika(pure goodness) intelligence. It bestows the symptoms of prema-bhakti. It is worshipable and is worty of being served by all. Sri nama fulfills everyone's desires. All are qualified to serve this maha-mantra, meaning all are qualified to perform sankirtana of the maha-mantra. This maha-mantra is the well-wisher of everyone and is endowed with the potency to attract all. It is the destroyer of all afflictions. It does not consider the rules of diksha, and is not restricted by time. The maha-mantra is worshiped just by saying it. No external paraphernalia is required. It is capable of giving results simply by it's contact with the tongue, without considering the rules pertaining to time, place and circumstance."

I hope this was of help to you,

Haribol!