I have found Poser to be pretty consistent across platforms. The shading problem relates to things with sharp angles, like the edge of a box. The trick to getting rid of it is to subdivide the polygons so that there are very narrow polygons near the edges of the object. If the polygons are very small that may also do the trick. DAZ has some info on this on their site somewhere. If you look in the area on broker submissions you should find a link.