It is Good Because it wins many people hearts by free 4G Data and unlimited call free.
There is some minor issue in JIO
You can’t use JIO as a Primary Sim because if You switch data connection in other sim than it’ll be disconnected and you wont be able to use jio for any purpose , not for incoming calls also.
Sometimes calls will be automatically redirected to any random person. I hope this Issue will be fixed in future.