No one can argue that airtel provide one of the best customer service in India. Let me explain you one incident when I used their missed call alert the amount of 30rs. Twice but when I compalined to customer care they solved my query in 10 minutes. No long waiting time to talk to their representative. Talking about their network coverage I personally never face such issue so network coverage is pretty good. Airtel provide two billing options postpaid and prepaid their charges are nominal but they should provide better 4g speed as they claim they are the fastest.