Airtel 4G experiences in Kolkata

Hi everyone, Thought of starting a thread for Airtel 4G experience in Kolkata* Speed test results.* Latency (ping test values)* Variation in speeds between peak / off peak times of the day (evenings)* Billing issues. (Airtel plans drop speed after download quota is reached and are unlimited in technical sense, but wondering if people are experiencing issues where download quota is used up much sooner than expected. We need to be careful not to blame Airtel when there is a software using up the download quota. Some hard figures would be good)* Does the USB modem switch between 2G / 3G/ 4G seamlessly?Thanks.