Speed post is the best service that Indian post start. I used this service many times to send important documents and couriers. Its the cheapest and faster service then private courier companies. Indian post is not good in my areas but in my area its best and they provide nice service as well too.
The price of sending documents is not much.I was send documents with bluedart courier service before but they was not fast in delivery and their charges was too much then speed post too. Afterthat I never use private courier companies service. Speed post is better and I trust on it.