I bought a jio sim 2 months after it was launched, the network connectivity is pretty good but not as good as vodafone, the main benefit of it is it offers data like no other service provider offers, previously all service providers would charge 300rs or so for 1GB data which was valid for a month, now jio offers 54 gb data - 54 days for a price of Rs. 309 .it is a game changer, vodafone and idea had to merge to tackle the growing customer bases of jio
call quality is not that good if you dont have a VOLTE phone, as you have to download an app which will work as caller instead of the stock caller, so you have switch on the data to make the calls
customer service is the best of JIO, as they are prompt to solve your complaints, I find this very nice
charges and billing is again the best as you get lifetime free calling, 1 GB data per day, thats more than enough if you use your phone for emails, google maps, youtube videos etc, my whole family uses JIO