I am using airtel for last 1 year and I never have any kind of problems with the service. My brother also using airtel in hosur for last 3 years and he is getting excellent coverage. He travelled across India as part of business for few months and he got excellent coverage everywhere. I got only two unknown calls by this period, I am using idea before, then there is a lot of unknown calls.
The call rates of airtel is very economocal for me. The customer care is also very good, they will respond to my enquiries on time. I have some problems with the GPRS connection settings with my LG C2600 mobile then airtel customer care executive will help me in solving the issues. I am using airtel GPRS card for last 4 months, its performance is excellent and in my opinion go for Airtel you will get Quality service