
Should we Read Shrimad Bhagwat Mahapuran or Bhagwat Geeta?
By reading Shrimad Bhagwat Mahapuran, the sins of infinite births are destroyed. By reading this, one gets as much virtue as performing a yagya (sacred ritual) like Ashwamedha yagya and even more than that. Bhagwat contains the essence of all the 18 Purans. That is why it has more importance. If a person reads Shrimad Bhagwat Mahapuran throughout his life, he attains Salvation in his birth.
Svānubhavākhila -śruti-sāram-ekam-adhyātma-dīpam-ati-titīrṣatāṃ tamo’dhvam |Saṃsāriṇāṃ karuṇayā’ha purāṇa-guhyaṃ taṃ vyāsa-sūnum-upayāmi gurum munīnām ||- Shrimad Bhagwat Mahapuran (1.2)
Shukadeva (Who dictated the Bhagwat to King Parikshit), is the Guide of saints and out of kindness for people stuck in worldly life, he shared the deep secrets of in Shrimad Bhagwat Mahapuran. Based on his own spiritual experience, he brought together the true essence of the Vedas and lit the lamp of wisdom for those who want to escape the darkness of ignorance.
You can also read the Bhagavad Gita as per your wish, but according to Bhavishya Malika, Shrimad Bhagwat Mahapuran along with Trisandhya and 'Madhav' name chanting, is necessary for salvation at the end of Kaliyuga and to get protected from the destruction.