I've written a comprehensive review of Noise Ninja 2. It's a 28 page .PDF download that's free to the digital photography community. http://www.thelightsright.com/NoiseNinja2
If you're considering noise reduction software, I hope this review helps.
I also have similar reviews for Nik Dfine 2 and Noiseware 4 http://www.thelightsright.com/NikDfine2 http://www.thelightsright.com/Noiseware4
I have plans for several more reviews of noise reduction software. I hope to get Neat Image online soon. That will finish the "Big 4" apps. I will also be looking at Topaz, PictureCooler, Akvis NoiseBuster, etc.
I can't predict when I'll complete the others. I do this as time permits. These reviews are quite comprehensive, so they take a while to prepare. They compete with my tools, tutorials, and videos for my attention.
Comments are welcome.