I use BSNL for my personal number linked with various online portals.
The best thing is, I don't receive any tele-marketing calls any day, because at my home and office, BSNL network is always "not reachable".
But today I got harassed very much, I wanted to book an online appointment and needed OTP for verification. I walked 20-30 mtrs in this scorching heat outside my office just to be in the network area and get the OTP . and ended up wasting atleast 1 hour.
I use BSNL for 2 reasons, one is to avoid telemarketers and 2nd is Patriotism (to help country's in-debt asset).
Many times I think- Wish I were in USA, atleast I could sue the companies for harassing me.
Pro-tip: Never use BSNL for personal number linked with Adhar.