One extra thing I noticed in differences. I created a render with 1 iteration... about as grainy as it gets and tested it again. The nvidia, external denoiser does a nice job connecting lines, where as the Daz one does a better job with more vibrant colours and highlights. After noticing this, I looked at my 50 iteration tests and noticed that even more. The external nvidia version made parts of the hair more straight and smooth as it found the lines etc... but it is duller. The Daz denoiser highlights where light reflects better and the colour is more vibrant by far.
Here's the original...
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This is the Daz denoiser...
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And this is the NVidia, external denoiser...
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The external denoiser, while better at joining lines, is way too dull without the highlights. And of course this is only 1 iteration, with the normal amount of iterations (400 in my case), you can't really see much difference except the NVidia external denoised version isn't as vibrant without the same highlights.
I imagine when you test it with water, fire etc... you should notice a difference in that respect, especially with reflections off water. I would expect the external denoiser to be worse for those.
Anyhow... SEE WHAT YOU STARTED!!! LMAO...
I also read that using Denoise Alpha in Daz can double your denoising times, so... as always, I tested that to death as well. I only denoise on the last iteration, so the times will be very close... in fact, in my tests, there wasn't much difference in times at all, like 0.1 - 0.3 seconds, I blink slower, hehehe).
(edit: I thought I posted this message yesterday, and I didn't... weird)