The only major thing I've noticed about the 9.5 release is that PRIME has gotten a little slower. I don't know if they've been able to pull out a bit more quality, but it does seem slower than it was when they first released it. I'm happy to wait for it given the results, of course.
Let me/us know if you discover anything or read about changes in the PRIME output. Or is there already some tutorial available when PRIME makes sense?
I tried it with a DxO trial version back then and discovered that it takes 15min to process a 20mp file on my laptop so I didn't have the time to experiment with it. In hindsight, the output didn't seem to be always that superior to Lightroom/ACR *if* not going for 100% output resolution, but downsizing and sharpening a bit. PRIME is certainly overkill for your average iso3200 shot. It might be better for extremely noisy shots like iso 12800 underexposed - it's just that I don't do these anyway.
For some of my shots, PRIME turned out to be rather mushy, my preference in these cases would be to keep a little "nice" 6D noise in LR as it looks better to me. Probably the same reason mpeg4 asp videos sometimes look better than mpeg4 avc with stronger deblocking.
I believe Lightrooms noise reduction algorithm was updated 1-2 years ago. I stopped using Topaz denoise, as I hardly could see any difference. Tested Dxo now, can hardly see much difference, alltough it might be there.
Reverting to ligthroom with the pitcure, it puts it in another collection....! Not like other plugins which does it properly in same.
You really must want to get rid of 5% more niose to go through all this, given that Ligthrom is your core tool.