I bought two. The first one I bought worked so well that I bought another. My dad caught wind of it and asked to borrow the second one for awhile. After having it for a couple days, he remarked how much better his breathing was at night -- we both have sleep apnea.
After being in the same room with the IB for awhile, my breathing does get easier, because my sinus problems start to go down.
If they are gimmicks, they must be magical, because I can tell the difference.