I am using Tata docomo since last 7 years. I was using docomo as it was initially plan like tata to tata free calling for one number which was useful during my enggagment.:) Even Docomo has good plan till last year(in 250 rupees I was geting 1GB 3G and 200 rupees talktime) But I always felt network issue with tata docomo.
Even today also they have good rates compatre with other operator but they have to give it as they have major network issue.They should seriously think of providing good network
My suggestion to go with docomo only if your area has good network with docomo else go with other option.