I have the Nightmare Blu-ray and find the transfer to be good, but it doesn't have the same depth as the theatrical presentation I saw recently. The Blu-ray is soft in comparison.
I'm about as anal as they come when dealing with A/V issues, and I've always demanded the absolute best quality given the available technology. The unfortunate truth is that economics do play a part in all this, and most films won't be provided a technician who will sit down after the encoding is complete and examine all 172,800 frames (assuming 120 minutes) for DNR artifacts.
My response to that is simple: knock it off with the DNR. All too often, DNR is used as a tool to cover up flaws in a worn film negative that wasn't properly restored, a second generation print with more noticeable grain, or an older HD master that should've been redone using better stock.
I'd hoped that the high resolution of Blu-ray would get studios to step up their game; flaws are much easier to see in HD. Sadly, some are taking the easy route and masking flaws with digital tomfoolery that ends up destroying the detail enthusiasts are looking for. The problem is that most of the viewing public likes these DNR'd releases for having the "clarity" of Monday night football HD broadcasts, much like they enjoy the muddy bass of a Bose cube system as opposed to the subtle nuances of a properly set up and calibrated audio system.