Hi there, I have been using Tata DoCoMo sonce 2009 when they first came up with 1 Paisa per Sec calling & 1GB internet for 47.
I am pretty much happy with it, coz it provides me good schemes as well as good network in my area.
Yes there are some areas or somewhere underground you may not get network there but still I very rarely face Network problem in my area.
While travelling also I don't face much network problem.
Overall just check the network Coverage in your area befor purchasing coz it's a total value for Money Operator