I have been using BSNL Mobile (prepaid) for nearly five years - and used it in two different states where I stayed during this period and barely faced any problem. Only once I faced problem was when on roaming the home city was not getting connected - which was promptly rectified on visit to nearest BSNL exchange.
I would say there are many good services that are available that BSNL does not properly advertise.
One of this relates to phone backup - and this was a chance discovery by me.I write this review relating to this service.
While deleting my SMSs (which clog my mobile), I chanced upon this SMS that said about phone backup. I accessed the particular link on mobile - firstly to my utter dismay - it said that the particular backup service has been activated and Rs. 30 deducted. I was totally dismayed and confused. I thought it was some sort of money making trick of the company. However, thereafter, I thought if Rs. 30 has been deducted, I should see what all this is all about.