Mark has produced a very useful and well written review of the Topaz Denoise program and I would like to add a few of my own comments for discussion. My progression in NR programs is similar to Mark's. I had used NeatImage, then NoiseNinja and finally Noiseware, settling on the latter for my routine work.
I downloaded the trial version of Topaz Denoise and tried it out on some images taken with the Nikon D3 at ISO and rendered into PSCS5 with ACR 6.1 (64 bit Win 7). Since one doesn't want to sharpen noise, I turned of all sharpening in ACR. I also turned off luminance and color NR, but am not sure if this is the right thing to do. Color NR might best be accomplished from the raw file.
I adjusted luminance and color NR to get a good looking result at 100% and adjusted the detail slider to increase sharpness a bit. The question is, should one use the detail slider for this purpose or rely on subsequent capture sharpening for this task? I then performed capture sharpening with PK medium and then output sharpening for an 11.8 x 17.73 inch print at 240 PPI. Of course, this brings back noise, especially chrominance noise.
The results are shown below with crops at 100%. No sharpening is on the bottom, capture sharpening only in the middle and both capture and output sharpening on the top.
[attachment=22418:TopazCompos.png]
Comments on the best work flow are welcome. More chrominance NR would seem appropriate.
One difference clearly noticeable between Noiseware and Topaz is speed: on my i7 system, processing time was 42 and 6 seconds respectively.