I am used Airtel, Vodafone & Jio 4G in mumbai and I analyst sometimes JIO 4G Speed is better than Airtel& Vodafone.
I am fully satisfied with JIO 4G. But on Calling Time I am very disappointed with Reliance Jio. Most of the time call not connect.
You need to always turn on 4G if you want to call someone.
Call Quality is very poor, even on VOLTE.
Call quality get more poor while downloading or uploading something on internet.