Jio is by far the most satisfactory voice and SMS service in Mumbai. And since it’s launched on 4G concept this service wont cheat you like other competitors who charge you 4G rates and serve you still with 3G towers. The best way to check this out is the symbol of your service provider. If its showing HT+ then you are being provided 3G services at 4G costs and if its showing 4G volte then it’s genuine 4g service. JIO promises you hassle free connectivity and gives you uncompromising 4G advantage across Mumbai. All thanks to Reliance Jio’s lavish investments in setting up a quality infrastructural framework. The voice clarity is amazing and I have experiences no instances of call drop or voice echo. As of now the company provides free voice calling to any network but the offer will soon be revised after 31st March 2017. But there is only one hindrance to this service. You need to have a 4 G enabled phone and make sure that the jio sim is fitted in the primary sim slot for optimum results. The first few days will have connectivity problems but after approximately two weeks the service reaches to its optimum level. Good service but with initial connectivity problems but still the best in its class.