Well, I would like to add to the comments here that Yes it does work and also its true that they give 1GB data not in one go but 50% when you recharge and remaining within 48 hrs ( sometimes within few hours). Just make sure you apply this on a GSM sim with voice services active and not on the data only connection taken for use in the dongles. By the way if you find any better plans than this one with some other operator do share your finds here.
Nextra FFTH connection is also good offer but services are not available everywhere (10Mbps symmetric @ Rs 999 per month for 20 GB data FUP then 512kbps, FUP ugradable in steps of Rs 300 for next 10/20/30 GB)