All of the flutter valves available work very much in the same way and produce pretty much the same results. Some people do prefer one over the others, but they are rather like most of the meds we have available. Some work much better than others for some people, but we can't say who will respond best to an Aerobika versus an Acapella. It's a matter of trying and finding one that works for you. If you try one and it doesn't see to work, be sure you're using in correctly (you may have to find an RT or nurse to help you) and if it still doesn't seem to do the job, try a different one.