BurrMan says: "The "resolution" of your print is going to be more limited by the physical printer, than the poly count of the model..."

He is absolutely correct. Your printer resolution overrides any minor surface flaws in your model - you won't see them. The 3D printer doesn't know about polys, it simply draws (prints) in 2D planar curves, moves the Z axis up a bit, and draws (prints) the next set of curves on top.

I don't know what resolution Shapeways has, but on my home printer I typically print at 0.1 inch layer height which is the vertical resolution. The horizontal resolution is much better. I simply export STL from MoI with the slider set for maximum resolution. My printer's nozzle is 0.4mm diameter, and that is what sets the horizontal resolution limit in practice.

The limitations of the printer do influence the way you design the model. In my case I print mostly mechanical items that fit together as opposed to organic "artsy" items. I've somewhat learned how to adjust my designs for tolerance when they must fit together.

Ed Ferguson