My Son Has Been Using Flovent For Over Year And

My son has been using Flovent for over year and is had good results. He is now using a different inhaler called Asmanex twisthaler and is short of breath by the end of the day. Is it a good replacement? Or should he go on something like Qvar? My new prescription plan of my insurance is now refusing to pay for Flovent. We need a good alternative.