I have been using a Jio sim from the past onw year. The packages provided by jio are cheap when compared to other telephone service providers. But, the internet speed has not been upto the standards of a 4G network. Especially in certain areas, the internet speed is very very low.
I also made a complaint regarding the slow internet to which I was told that it would take 90 days as they were adding some towers in the area to meet the demands. However, 90 days is a long time.
Apart from the speed, jio provides other services at really low cost.