I downloaded this and gave it a try using the 30 free trial …
My current system is Lightroom 5.7 on Winows 10 supported primarily with Topaz plugins. But I also have the free Google Nik collection, Affinity Photo, and a handful of other tools. My gear is older - Nikon D40 and D7000 - so my needs are likely different than those of you with much newer gear and many more megapixels. I do own an older version of DxO Pro 7 which produces good results, but I came to prefer my Lightroom workflow and stopped using it years ago.
If you try this, you have a choice to just get PhotoLab Essentials or PhotoLab Elite. I found this link to help with this decision: Essentials vs Elite feature list. I installed the Essentials plus Nik package.
During install, it said older versions of Nik would be removed. So I cancelled, made a copy of my Google Nik directory and renamed the original directory, and restarted the install. This probably wasn’t necessary, as DxO installed their Nik software in a sub-directory of the PhotoLab2 install location, and my old Nik is in a Google sub-folder.
Photolab worked well with the Nik apps as a complete, standalone package/workflow. Of course my main interest was whether the ability to call PhotoLab from LR, and the combined package of PhotoLab2 and Nik offered benefits that would prompt me to change my workflow.
The first time I ran LR after the install, a message box opened indicating the PhotoLab2 plugin was successfully added to LR. The Nik plugins were also individually listed in my right-click Edit In menu. I was able to run PhotoLab2 from LR and then run Nik within PhotoLab2, and I was able to run the Nik plugins directly from LR. Supposedly, your saved work is placed in a new collection back in LR. However, in both cases no new collection was created. The results were saved in the correct LR library folder, but had to be imported if I wanted to do more work in LR.
My understanding is that the DxO Nik Collection plugins have no new features only new presets. The new capability is that I can call PhotoLab 2 from LR and save back to LR as TIFF or raw DNG (though as mentioned above, I have to import those manually.) I could not call DxO 7 Pro from LR. So this new feature does make it much more practical to have a workflow starting in LR.
However, I’m going to pass on this for now. The Google Nik plugins are essentially identical in function. They are accessible directly from LR, and when I save, the results are imported but not added to the collection. This is OK because I may want to put the result in a new collection anyway, and it’s very quick and easy to select the image and add it to any collection versus going through the import process.
Incidentally, I did have to reinstall my Google Nik software after this, because Windows and LR lost track of the location. Fortunately I still have my Google install .exe.
Anyway, just thought I’d post my experience and choice.