I had broken my nose as a teenager, and thereafter suffered from chronic sinusitis and nosebleeds. In 1987, I had surgery on my nose to remove damaged cartilage to allow me to breathe easier. About ten years ago, the sinuses got so bad, being clogged almost constantly, that I finally had surgery to open them up. Since that surgery, I have much less issue with my sinuses, but more with allergies.
Since I started diving in 2003, I have had a little trouble clearing my ears on descent, regardless of how slowly I descend or how often I clear. Decongestants seemed to make it easier, but I still had problems. On a dive in Key Largo, in 2006, I "forced the issue" in getting down, and suffered from middle ear barotrauma, according to DAN.
Also, when I fly for long distances, I have found that on returning from a dive trip I usually end up with a very bad cold or sinus infection.
I started using the Neil Med rinse in March, prior to a trip to Fiji. I used it on the plane going over, twice a day while there, then once again coming back. I had no trouble clearing on any of my dives, despite the fact that I used no decongestants whatsoever. When I returned from the trip, for the first time, I had no cold or sinus infection.
I followed the same routine in Roatan, in May, then again in December, for a non-diving trip to Turkey. Again, no problems, and I have not had to take any decongestants.
In addition to travel-related issues with sinuses and colds, I often wake up and I am stuffy. I find that if I give my nasal passages a good rinse, it usually clears me up quickly and I can breathe normally.
Needless to say, I'm a believer and will continue to use Neil Med.