I think in today those have 4G smartphone they have Jio Sim. I also used this network of Jio Operator from 1.5 years and it's excellent voice quality and the internet speed also. I think Jio opeator service is best. If I travelling from my local area to another city no problem facing from the network issue. In few days ago, I facing problem from internet speed and called to customer service and they help and it would be solved in few hours. And the Jio has good customer support as well as service. So, Jio is good network operator.
Thank You