I really hope that BSNL is giving better plans than they are advertising as most other ISPs do. I had taken a VSNL (now tata) broadband in 2002 with 64kbps unlimited at Rs.1000/- and they doubled the speed every 2 years. By 2008 they had 512kbps at the same cost. However their website never showed these schemes. My plan was Rs.300 cheaper than what they advertised on their website.
In 2012 I shifted to Asianet BB - 512kbps at Rs.520/- After a years they offered me an upgrade to 1Mbps hidden scheme that is not listed on their website at Rs.580/pm.
The only ISP that mentions their real speed and price is Reliance. Everyone else is playing games with each other by hiding their real plans from competitors. The ISPs who are late into this game are Airtel and BSNL who are now trying to offer some schemes to retain customers.