I am using Airtel for more than two years and I can say that it is one of the best network provider to my opinion. its network coverage is outstanding and I am getting tower even in the deepest area. Airtel 3g is also very fast as compared to other networks and its customer service is far better than other services, customer care executives are polite and handles situation finely. as concerned with charges and billing it is slightly costlier than any other service providers. but I say it is good among all.