2 years ago I chose airtel as my primary sim card. Airtel's local calling is good but whenever I tried to call outside of mumbai it become very frustrating. When I upgrade to 4g, I thought it will be good for video calling. But again I got upset. 4g works horribly in my area. Sometime it backdowns 4g to 3g. Downloading speed is very low. I hardly run live quiz app like loco etc.
