I am using airtel 4G from last one month and I encountered many difficulties firstly was that signal strength is very bad in delhi and in many areas in NCR 4G is not available, leave remote areas. In Delhi the speed of 4G is same as as 3G . We cant use 4G data as 3G data so it can be used in 4G hotspots and new mobiles because maximum people have 3G mobiles only.