Airtel is one of the most popular network in all over the world, because there network is everywhere while comparing to other networks, and also other networks will not cover some village places but airtel is only one who provide network every where, and yes there 4G service is mind blowing, we can download everything in just few seconds.
I tried so many other networks also but as per my experience I must say that airtel has the best density. Call rates are little expensive than other networks, but we dont see the rates when we get the best service in just a little more money.