What we want mostly in our phones? It is a good network. So if it comes to DOCOMO the network is the poorest. I dont know why TATA is not improving their network quality. In most of the areas their is no network and while talking to someone the network goes off.
While DOCOMO catches signal in metro, subways, etc I mean underground areas. But no one will be staying at those places for most of the time. Tata Docomo should improve is signal strengthens.