I have been using jio sim since many days and I would say that the network provider is good but sometimes the network is not stable it fluctuates and there is a decrease in the speed.
The other thing which is very bad in jio is that u cannot connect the call. Like u ll have to try for some 4-5 times after that the call may get connected or else u have to keep trying.
The best thing about jio is that UNLIMITED HOURS from 2am to 5am u can download unlimited data with best speed so according to me jio is the best sim for now on the market except for some flaws which I think will surely be solved within few days