Not a fair comparison with 3D printing as these are big models.
For at least 25 years now, I have bought and built kits made in different technologies.
Regarding the 3 D models, mainly in various "G"-Scales, including Gn15, in almost all of the cases I had to spend time and money to add details like nut and bolts castings plus many more details, simply because the designers omitted them.
So please show me a complete 3 D printed Gn15 kit, fully detailed, in the 20 Brit Pounds price range.
There is a lot of poor but overpriced 3 D printings offered these days. This turns the potential customers off. I will take a long time, to repair the damage done to the 3 D market by these kind of offerings. I know that there are some excellent 3 D models offered in various scales, but a lot of rubbish as well.
I am always curious to learn about new technologies. If they offer affordable quality, I will think of embracing them. A friend of mine recently bought a 3 D printer and his first 7 / 8th attemps look very promising. http://www.die-feldbahnsinnigen.de/forum/viewtopic.php?f=65&t=1840
So until he goes professional, I will order me some more ModelEarth Budget kits. I don´t lnow, if I still will be around in 5 years. But until then, I simply want to enjoy and play with good quality toys.