For BSNL if the same site same time upload / down load is 1KB.
Reliance would result in 1 MB. This is how they cheat while you exceed your free usage.
You can cross check this very easily if at all you have been using the Reliance or any other.
Just see how the upload and download goes on increasing automatically even if you are static on a page and not surfing any other site.Speed also is way below they assure.
I think BSNL being a govt. company would never go into such cheating means. Finally to conclude , however bad may be (That some feel) I think BSNL is the best.
Because all others are worse or worst in terms of speed, cost.