Ideacellular is being used by me for last two years. The rates are competitive and the customer service is also good. But the main problem is that most of the time their website is slow or down and one is not able to do online recharge. Since I had ported from vodafone, I am unable to recharge in most of the sites, as idea itself denies that I am not their customer.
Another problem is that the signal strength is very poor in suburbs and its very difficult to talk from ground floor. You should be living in a tall building if you want to talk from inside the house. But other than that the billing and other services seems to be good. They can really install more towers and take more improvement regarding recharge related issues.