I got Topaz a couple months ago. Had a family wedding and took a lot of photos during the reception. Of course it was low light and there was noise. So I found a good set of photos to use Topaz Sharpen and DeNoise on. I use Topaz as plugins to Photoshop. I actually don't find that it speeds up my processing nor is it more convenient. Maybe when I upgrade my old computer that will help.

My experience (albeit limited) is that DeNoise works great. I had no problems with it except trying to determine the minimum amount to apply. The photos look much better than what I could do in Photoshop alone.

OTOH, Sharpen seems to be a mixed bag. Since it was a low light environment, there were shots where one person was sharp and another was slightly soft. Most of the time that was improved by Topaz Sharpen. It doesn't make the out of focus people sharp, but it does make them less out of focus. However, there were a couple of shots where it failed miserably, adding extraneous elements to peoples faces. I can't rule out inexperience with the program as the cause, but I tried several things, all with the same result. On the whole, it does better than PS alone, but not always.

I will keep using Topaz because I think that it improves photos more than PS alone. Hopefully practice will mitigate any problems I encountered.

Kind of what I'm saying. My thought might be clearer, if you reviewed the longer threads linked above, as the example posted from the airshow builds in the detailed ideas presented in the linked LR / UHH posts.

But toward 'yes', the defaults applied by LR upon RAW import are a pretty heavy noise reduction, only for Color NR. This will clean up a lot of noise, while also cleaning-out a lot of image detail. The sharpening default at RAW import will counter-act some of that Color NR default, but still, the images would (will) be much better when the digital editor (human) actually refines these default settings.

I don't have the Topaz AI tools to see how much smarter they perform than the LR import defaults. Again, as stated in my earlier comment, my older version of Topaz does a better job of smoothing out the color and luminance noise in the background, creating a very 'clean' all-over image, better than using just Lightroom alone. My technique is to use both tools together, when needed, but I have older software and don't have valid current versions to assess current performance.

No, I'm saying LR applies default settings to all RAW imports. Most LR novices don't recognize nor refine these at-import defaults. This example image isn't particularly noisy being ETTR in a bright light at ISO-1000.

Box 1 and the background canvas are an unedited image at ISO-1000 with the LR defaults. Box 2 is zeroing-out those LR default settings for an example version of the original RAW from the camera (alas, box 2 is really no visual difference vs box 1 in this section of blue sky). Box 3 is the fully edited image, but just a 500x500 crop of a darker section with Luminance and Color noise remaining in the sky. Box 4 is that same image from Box 3 run through Topaz to further clean-up the sky. For this example, the relevant comparison is boxes 3 and 4, but one needs also a view of the start-point (boxes 1 / 2). My point of these examples was to respond to a comment saying they failed to note a difference from Topaz, where I wanted to show even for an image that is relatively clean, Topaz does a great and noticeable job in the background details where noise hides in larger prints and / or higher resolution posts.

You can disparage LR sharpening, but that disparagement leaves me concerned you're not using the tool properly. The LR import defaults are insufficient and have no consideration of the masking nor image details. One needs to test for the pixel resolution of their camera(s) and the sharpness of their lenses, and they can find relatively general parameters, unique to their images, that are much more effective where they're sharpening the image details rather than the image noise.

Agreed, PS has many options / techniques. But, really, what do you need more than a masking setting (slider) and strength for sharpening? I'd say the 'detail' slider is relevant too, where if you use the <Alt> key to convert the display, again you get LR to sharpen the relevant image details rather than the image grain. These two links were provided earlier. They include screen captures showing the LR tools in action.

Basics of noise processing

Basics of Lightroom Sharpening

Markag, this is probably the start of a separate topic, but here's a quick example to address your post above.

I'd think you should be confident in shooting to ISO-6400 with a more modern Z7 than my EOS 5DIII that I try to limit to ISO-5000. The attachment below was developed from Lightroom v6 and PSE-10 using a recent image posted to Flickr from last weekend in Chicago, but not used in any posts to UHH.

What I wanted to show was LR's default processing when any RAW file is imported. There's a default total sharpening amount applied and a default Color Noise Reduction (with zero Luminance NR). My own experience with Sony and Canon EOS RAW files is that images in the range ISO-100 to say ISO-1600 need mostly Luminance NR rather than Color NR, and total NR much less severe than LR's default values applied to all RAW imports.

In the attachment below, I exported uncropped full-resolution images using history steps and then cropped a 500x500 pixel box of the same location of each image version, merging onto the top of the crop size of final version of this image (1709x1069px, down from the original 5706x3840).

To describe a bit further,

Box 1 is the LR export with the import defaults for sharpening and Color NR. The background canvas is the same #1 image
Box 2 is an LR virtual copy with the Sharpening and Color NR set to zero. The difference is subtle, the difference is visual when I turn the layers off and on in PSE, although you likely can't see an obvious difference between boxes 1 & 2 (I can't).
Box 3 is the edited version of the image I posted to Flickr after just LR processing. This image was nothing 'special' and I didn't take the addition effort to run it through Topaz DeNoise.
Box 4 This is the Topaz DeNoise v6 result of the same position as boxes 1,2,3. I'll probably replace the LR version in Flickr with this improved version.

What I find with Topaz is the DeNoise software is much better at cleaning the background details than LR. Therefore, my approach is edit as normal in LR, including sharpening and NR, either to completion of the image, or using the same settings 'as complete' and then process the uncropped image with the LR edits in Topaz DeNoise. I tweak the DeNoise settings to focus the de-noise effort on the background. There's a Topaz 'slider' for highlights that I set to minimum. I re-apply the final crop when re-importing the Topaz results back into LR.

Hopefully, the difference in box 4 is obvious compared to the other three crops. You should be seeing the same / similar in your work. When you say you don't, we'd really need to look at specific images, both original NEFs and your edited results, something that is definitely it's separate discussion and likely to need a dropbox for the file sharing.

To 'see' the details you need to launch the attachment into a new browser window, or download to your computer. Then, you need to click to the 1:1 pixel level details. At the 1:1 pixel level details is how you should be reviewing your Topaz results too.