Otto: That is my impression as well. The SeaLand containers I bought a while back are very well designed, and as close to perfectly scaled as I can measure. But the Shapeways prints took a LOT of cleanup, and I never did get them truly smooth, even though it's all flat surfaces.
Frankly, after seeing the "layering" lines, I was thinking that they'd be a good source for N scale small-lumber loads. The "artifacts" would be perfect for the sides of a not-quite-perfect stack of 1x lumber, without the usual "board gaps".