Digital BW, The Print

I've used all three and each has their strong points. 

I like Neatimage the best for particularly difficult images. I'm thinking
about grainy film scans and underexposed 1600 ISO images from my 350d. 

Neatimage will only make your images plasticky if you let it. The trick is
to leave enough grain in the image to make it look natural. A lot of
percieved detail lies in the texture of surfaces, and if you remove
everything it just doesn't look "right" anymore. 

I've sometimes had success with removing a little bit more noise than I
think looks good, and then doing surface sharpening of the resulting image
to brings back some of the noise, but with a more uniform noise pattern. I
also frequently use Grain Surgey to add grain back to my images. Grain
Surgery can do really nice film grain which looks much better than digital
noise.

Another thing you can do is apply heavy noise reduction to a copy of the
layer, sharpen, high pass and overlay to only sharpen detail and not the
grain.

Neatimage really needs a good noise profile to do it's job properly. If you
get artifacts in the image it's almost always because of a poor profile.
Neatimage supplies a target you can shoot to generate noise profiles for you
camera. I've done this at all ISO's with my 350d and RSP 2006.

For low and medium ISO exposures Noise Ninja will usually work equally well,
and much faster than Neatimage.

Noiseware can remove noise without needing a noise profile. This is great
for images from unknown sources where there is no suitable area in the image
to make a profile from. It can sometimes do a fantastic job on images where
Neatimage and Noise Ninja fails.

There is a learning curve with all of the tools. None of them will give you
optimal performance with their default settings. You really need to study
the documentation and try out all the different settings on various types of
images to get a good understanding of what they do.

--
Daniel Staver
http://daniel.staver.no