I am a prepaid tata docomo customer in kolkata. Though i am using Vodafone and bsnl mobile for the last 7 years i feel that docomo may be a good competitor for other operators. Docomo billing is excellent and affordable without any power recharges regarding voice calls and gprs data usages. I used docomo to connect to internet with my computer using my Nokia 3110c as modem and got excellent results. Although the speed is not as good as broadband but compared to others it is excellent. Gprs data charges are positive compared to voda and airtel. I may mention here docomo should give some plans for unlimited usages like bsnl mobile.
But docomo network is weak indoors in many places in kolkata. Also during a conversation the voice gets eclipsed quite often as if the connection is snapped but again comes back. Also the voice quality is sometimes interlaced with with a hissing sound. Here voda is superior !!
Docomo should rectify these and it is a guarantee (take it from a subscriber) that they will be no 1.