I have been using Airtel connection from last 6 months in Noida. THe locality were I live only Airtel is available. We dont have any other serivce. My connection is 512 kbps unlimited and airtel provides that speed without issues.
THe problem is that its inadequate in these day, I am paying 1200 INR for this speed and my friend are paying 1500-1600 INR for 4 MBPs or 8 MBPS internet. I inquired airtel for 1 MBPS internet which is costing 2200 INR per month. Thats insanely high pricing in any ways.
NOw they have some 5GB-40GB of high speed connection of upto 40 MBPS with each plan so they justify the plan but that data is used quite quickly and you are back to unlimited usage which is pretty bad.
So I think its best to avoid airet for internet since its quite pricey. I had a hathway connection earlier they were chargin 650 rs for 1 mbps plan, the connection got a bit slow at times and I used to get 750 kbps but that was still faster than this good 512 kbps provided by airtel and hence was great for me.