I don't use in-camera noise reduction because first it only works when you're shooting jpeg and I almost never do. I find I get digital artifacts that are later harder to get rid of. When shooting raw, I get a kind of grain that is very regular and it actually looks like the old film grain. Then with Camera raw or LR, it's easier to deal with. I can tolerate a little bit of grain since some noise reduction to excess can also bring loss of sharpness. But that's my taste, to each his own.