Form Vs Formless

Among the different Bhakti schools, the most prominent were the Nirguna and Saguna.

1. Nirguna School believed in formless God, whereas those belonging to Saguna worshipped a personal God with a form. Kabir who founded the Nirguna School of Bhakti conceived Rama as a formless God 
2. whereas Tulsidas and his followers worshipped Rama as Saguna God taking into account His divine qualities and achievements.

http://ramappearance.blogspot.com/2011/09/prominnent-disciple-disciples-disciples.html

Even the Nirguna School of Bhakti was split into two groups –

1. those who believed in ‘gyan’ (knowledge) and had an intellectual approach to devotion and 
2. those who believed in love and attachment, and total surrender to God for attaining Him. Those who followed the latter path were the Sufis or mystics. 

The Saguna school of Bhakti also branched into two directions, 

1. one devoted to ‘Rama’ was led by Tulsidas and 
2. the other for ‘Krishna’  latter by Surdas.