I am using airtel for past few year and quite satsifed with them ! Nice speed on 4G network but quite Bad price according to plans ! I think for sure that airtel network is available everywhere ! Upto 3 mb/s speed given by airtel around me ! But still the plan are big issue they are too much expensive than other and less profitable ! Customer care service is also good ! Airtel is one of the best 4G LTE network in india !