All three of them - Noiseware, Noise Ninja and Neat Image are very good products for reducing noise in digital captures. I have all of them and I've used them extensively. I find Neat Image works better than Noise Ninja for images from scanned negatives, but Noiseware seems good for film scans also (I have tried it with film, but not accumulated as much experience using it for that purpose). I think Noiseware does a slightly better job protecting detail then the others, but that is impressionistic - I've not done rigorous comparisons. I really believe regardless of which you use, the most important thing is to get the settings right for the image whose noise you are reducing. That probably makes more of a difference to outcomes than which of the three products you use. So the bottom line from me: a moderate preference for Noiseware, with much attention to settings no matter what. I agree with those who suggest testing them all. Costs nothing but time, ink and paper, and then you'll no for sure what is best for you.
