The last Williams brass loco offerings - their "Masterpiece Series" - contained an N&W 2-6-6-4, as I recall. I have the Century and un-streamlined NYC Hudson from this group. Well-done, high-end look. Mine run well; I need to upgrade them.... The same builder did the Smithsonian Lionel brass Hudsons, to my knowledge, and I believe that whoever that was did some 3rd Rail production, too.
I would go that way for display; for running I would probably go Lionel (I have one) or MTH (a friend has one), but I honestly feel that any would do both well. Lionel has TMCC, no Odyssey (it's kind of an early piece). Good brass has a certain crisp look - fewer "thick" spots.
Unless you are a 2-railer, for a true shelf queen, I'd go 2-rail. Not sure about 2-rail production of this loco through the years.