I use idea postpaid network in Madhya Pradesh & Chattisgarh.
Network - My job involves lots of traveling and network gets weak while in train but otherwise it is good.
Cost - It is a costly operator compared to others. The data pack and mobile charges are high but I have a monthly plan so it doesn’t make much difference to me. If you don’t have a pack, you will end up paying higher.
Customer care - Worst customer care ever. If I miss to pay the bill by due date they just block all my network, internet. And even after paying the bill after due date, they take a whole day to unblock my services which is very frustrating. The customer care is least bothered.
Internet - The internet is of a good speed with mobile data. I do not face problems mostly with it.
But I will still suggest to not use this network.