Above all airtel is the best mobile network is known to all. If you ask me then I would say there is no network in India which can compete airtel. The factor is all the networks are found easily over town areas but where they fail are villages and inside areas where no other network found. Which are the no network coverage area for all other networks but here airtel flies high. Thus the country demand for airtel and it worth it. And for smartphone network or 4G services airtel performance is remarkable. It's 4G speed is highest above all networks as I know. And now it is a open network and thus airtel deserves to be the best.
