I am using this network as a secondary network but my experience with this network is very good that is why this is my oldest network which is never change although I have change other GSM sims but never change this.
This is my first operator although some places its network does not work but its offers are good. One time there came an offer of portability but I said no at once. I do not want to make any changes in this sim.
One day I have lost my mobile with sim. But again I issued the same number with same service. One more thing TATA DOCOMO OPERATOR changes its services, Plans Offers time to time for better exoperience.