Using loop mobile now for a couple of years.Good calling rates, and they have exciting new plans but data service is the main draw back one of the worst data service. Only useful if you are Mumbai local!
apart from data service calling rates and network coverage is quite good.and rates are also pretty cheap.
Customer services are not up to the mark suppose you are having a issue, then in order to get in touch with them is a big task they will keep on hold for minutes.