I never got promised speeds, bad customer support and no one would pay attention to my problems.
I used it for 3 months and then threw it away. It was that bad. Speeds were 200kbps(for 3G) and it seems to be the case with most users.
Customer support is junk and they dont give any importance to your problems. I would NEVER recommend Airtel to anyone.
You would be much better off using you mobile as a modem than using the Airtel data card.