I am also using Airtel sim.
I have been using this sim since 2011.before 2016 service of AIRTEL is too good in comparison of other network.but Now, there are many problem in the network.
And inside a home not even a single network is catched by my phone. And many time I missed my important call due to poor quality network.Now I am planning to port my number in other network. So I will suggest to everybody dont connet with airtel network.