I would be hesitant to use P&R as an indicator of quality if for no other reason than it, in and of itself, doesn't distinguish the firearms that everyone waxes poetic over from those produced during darkest Bangor Punta.
This is not to say that BP era firearms blew chunks - most, perhaps nearly all, were products that would make S&W proud. Anecdotally, one of my favorites is a 5" nickel model 27 which exhibits all the qualities associated with expert craftsmanship. Best as I can tell it may well have been made at nearly the same time and possibly in a workstation adjacent to the one which produced my 28-2 which is a dog's dinner of Bangor Punta horror stories that would make Charter Arms blush on their worst day. Then there's the 57 no dash that split the difference.
MIM would seem to be an issue which is treated differently in the world of firearms than in the world at large. I'm not saying the view of the process in the firearms field is wrong. It is perhaps, on rare occasion,
dated.
[Seinfeld]
Nothing wrong with that. No sir, nothing.
[/Seinfeld]
The MIM process is relatively new and advances come at too fast a pace for me to keep pace with (my ASM membership lapsed before MIM was commercially viable). However, I do know that available relative densities exceeded 99% some years back. As of two years ago 3.5 pound flow control assemblies for passenger jets became reality in MIM and, if density vs. SAE 4140 is an issue it's easy enough to use a
specialty alloy. MIM can also be polished, plated, heat treated and machined. A MIM tungsten hammer will make a primer think it's been hit with the hammer of Thor.
This is not to challenge any observations previously made here as I will make the obvious observation that what is available with MIM may have little or nothing to do with what S&W has seen fit to implement with the process. Or, most especially, <shudder> Kimber's early forays into the process.
Anecdotally again, and admittedly lacking the Fuff's numerous examples (my oldest unmolested example being from 1948), the finest fit and finished examples of S&W are P&R - several from the BP years.
The one I shoot best, out of the box, is a 2008 627. Arguably, putting the maximum number of rounds downrange, quickly, where one intends for them to go, repeatedly, is what Smith & Wesson intended back in the 19th century. At the job of actually doing what a revolver was, I believe, intended to do, the 2008 PC version comports itself well.
In the interest of full disclosure, the late model 627 has a forged (blanked / conventional) hammer and trigger. Whereas some of my earlier non-locked examples have MIM. I'll not re-open that can.
Lastly, though the OP already mentioned it, P&R only applies to S&W's slide into perdition. The Colt Python, introduced around 1955 if memory serves, is without recessed chambers, a pinned barrel and even has a frame mounted firing pin. And everyone knows how those Pythons represented a general decline in Colt's quality.