Being the largest indian cellular network airtel is just good and fast.its network coverage is superb. Even in the remote area of the country you will always be connected to your friends and family. And in the matter of internet connectivity, there are no competitor. It is best in 2g, 3g, and ofcourse in 4G.
But its all services like calling, internet, 3g 2g are very expansive hence it is not for all. Except this everything is beat.