I am using Idea network since 2010 and recently got the network sim upgrade to 4G and now its working fantastic in Gurgaon and other regions as well.
Network comes in basement as well there is no problem in making calls and messages.
Internet speed is awesome it goes up to 4 mb/s downloading. And videos/movies does not buffer.
Customer service is good, sometimes I face some issue or need help then I call customer care and they resolve the issue politely ASAP.
Overall Idea network is good and I am having a great experience with it.