I've been reading a lot about the many differences, pros and cons between NURBS and polys, but is there a difference when it comes to 3D printing?
The printed model is typically polygonized before printing - it's easier to do things like watertightness checks and so on using triangle meshes. A nurbs model can be polygonized at various resolutions, so it should be possible to get a higher quality, smoother looking print by starting with a NURBS model and using a very generous tesselation at printing time. The tesselation may not always produce a watertight mesh - depending on the software used to do the printing that might cause problems which need to be fixed up by hand.
So, overall the main advantage of a nurbs model in this context is that you can work with a more efficient, lightweight representation of the data up until its time to print: the final printed mesh may be impractically dense for most ordinary applications (millions of triangles).