Reliance jio is the most popular telecom service. As it offers free internet to several thousands of peoples for a long period of time. The data tranfer speed of reliancejio is very good. But when it comes to voice calling it lacks a bit due to the cross talks between various jio numbers. You can observe mostly in the evening hours the calling from jio is not connected. Also if it connects then it may onnects to a wrong subscriber. Also sometimes there is background noise. If these can be resloved then it is number 1.