It really depends on the kind of material that you are using, it depends on the size. Please use WSf and ceramics for smoothing. It gets nicely rounded if done well. In blender export ObJ and try to subdivide it. You also consider making the facets smaller, try correcting the edges which might be creased in Blender. And always before designing try to keep the 'smoothing' from the option turned OFF. Then after you complete it F9 should do the trick.
Lastly run your file through Truespace for final smoothing and that's all. Best of Luck!