My experience with Airtel from the day (two years ago) I started with them has been one of quick service. Airtel makes use of the usage metrics to offer you better service and I like that part.
The connectivity is as claimed -10% of the speed you sign up for. They have a rather obtruse process to get onto the ECS facility and that’s a pain point; many payment centres notwithstanding, one would expect a telecom company to have an easy/simple process for customers to pay their bills, including for paying by plastic online.
I have the combo plan which gives a free landline connection alongwith the broadband. (on the landline, the ring tone songs on offer are quite good. Recently there was a quiz game with decent prizes -attractive and smart but need to wait and see if there’s any golmaal to it) Generally, Airtel provides a decent service that is value for the money you pay.
The facility to "rent" antivirus software (monthly payment) is helpful I think; I don’t trust the particular brand that Airtel has tied up with but the pricing is innovative. Installation of the broadband connection, or servicing any instrument or line failures are done very quickly.