FDM machines just don't pass muster for the types of models I usually want to create. I want a finish that's close to the injected-molded styrene models that I'm used to building. I designed the HO scale truck trailer below and had it printed at Shapeways. I doubt you could do that with an FDM machine.

http://i1089.photobucket.com/albums/...ps7c400f46.png

I might also try i.materialise. I've heard they allow you to specify the orientation of the model, which can help to smooth out flat, horizontal surfaces. Shapeways doesn't allow you to specify this. They orient the models to make the most efficient use of the volume.

Steve S