In Delhi work well but once you leave delhi it drops network towards chandigarh and himachal. No signal at all are shown on your mobile due to poor network. In other words Airtel never break your signal even you hv gone in deep tunnel and or any deep place. In plane wise rate are some compare to Airtel.
As Aitel has already brought his 4G more than one year back but Vodafone just trying to launch and dont know whether it will work or not.
But Airtel deserve the stars surely.