I really don't mean to offend anyone by saying this but I feel it needs to be said... The resin kits of 'obscure' prototypes are respectable. The one thing that gets to me about them is the minute flaws that come with them. Yes, not all have them but they do show up. Hence my preference for the Shapeways approach, which should minimize them - more so if the resolution of 3D printing gets improved. And the benefit of doing it in 3D printing now is, when the resolution does get bumped up, the e-files will be there to get better models made in the new resolution.
There are a few flaws I have seen with the 3D approach I have seen. For one, the tech is not for every model, or every part of a model. Some stuff is better suited for etching and there's no way to combine printed and etched parts unless the 'manufacturer' (the file creator, not Shapeways) takes each part in house and packages it. It would be great if Shapeways offered etching or there was an etching company that took up the 2nd-party-provides-file-for-3rd-party-to-buy-JIT. For instance, passenger cars, for the most part, are best done with etched sides, with core, roof, underside, etc. to be 3D printed.
Another flaw is that some product creators print an intricate model as one piece, when it would be easier to work with (refine) if it came in parts. The wine tank car is one that comes to mind there.
Last is decals. N scale decals to complete obscure models are still woefully absent.
