Its a good plan. I am a user of Reliance BB 3G data dongle (was using Tata before) and reliance experience is vastly better. At least in this division the company has changed for the better in the last 2 years.
Just compare the websites of Reliance and Airtel. Reliance site is much more user friendly.
The only problem with wired BB is that Reliance does not have coverage in all areas of Kolkata.