I use airtel network 2010 to 2016 the performance of this operate is brilliant.
My first airtel sim is 2G network in my 2G support mobile I convert this 2G to 3G in 2013 and the net performance is excellent I purchase a mobile with 3G support in present I convert a sim in 3G to 4G. Airtel provide best call quality in monsoon the network is coverage in all weathers.