I am using Airtel sim for 6 years and Airtel sim provides us awesome service anywhere, anytime.
Anywhere you get airtel network and internet speed is as fast as rocket.
Airtel internet package are in 3G and 4G - rs.9 we get 25MB for 1day and most attractive internet package in my opinion is rs.51 which provides us 1GB internet both 3G/4G for 12a.m. to 6a.m. nights 1 day and these net are very super fast. Though these packs are very costly for simple man but you love net speed than you will use airtel sim. Airtel customer care service is awesome and good behave. And airtel provides us free hello tune and 27% bounce and more offers. So, I suggest to all Indian people that you must use this Airtel sim.