Last few years I am using airtel, still now I dont have signal problems , but call cost are high on airtel, internet cost also too high on airtel, I prefer it is truly the fastest internet when compared to the others , I used airtel 4g its mind blowing bit its cost too high I am not able to recharge it regularly, also some of the middle class people not able to recharge with airtel, airtel only suits for high class peoples