I bought a relance lyf jio phone a month ago for the phone and specially for the 4g serivce provided by them without a doubt it was fast at the start but now it is bit slow but still I can say the fastest 4g service in India right now.the phone is also working perfectly up until now.
I have tried to play all youtube videos at 1080 p amd the videos are getting played without stoping easily some times it does get slow but I guess the network is growing day by day at a fast pace so it explains why it is getting slow but it is pretty awsome.