Based on my website stats so far this month, visitors are much more interested in Noiseware than the other options.
Noiseware has more visits to its
info page than the others (#12 out of all site pages). Noise Ninja was the next most popular of the three, but way down the list.
The phrase "noiseware" is more often searched (74 times, the #2 most used Search Keyphrase after "
lucis art").
Other related successful search phrases this month (in descending order of hits) were "noiseware coupon code", "noiseware coupon", "noiseware discount", "imagenomic noiseware coupon code", "noise ninja", "noiseware code", "noiseware & mac", "noise ninja pro discount", "ninja noise", "noiseware professional edition for mobile". Neat Image was searched for only twice.
I personally use Noiseware, although I've got all three of the above plug-ins (as well as NoiseFixer, NoiseBuster and Noise Reduction Pro).