I have the airtel sim card which give normal response.My friend who live in different areas have airtel sim card and the said that they are very happy with the service as the get proper network and have never faced any problem with any issue.
We is my friends who r using different sim cards says that they did not get proper services and network.They also switched to airtel.
There is only one issue according to me i.e., their is no proper network in my area in navi Mumbai.its very hard to get network over there.and this thing I don’t like other things are OK with airtel.There have not been any billing disputes in my case or my friend.This is very good operator.