the upper arms look very strange to me, the legths, musculature and ratio to the lower arms looks very odd. Is that an anime style thing? the joins of the head/neck chest also looks a little odd, but works stylistically

As far as mesh desnity affecting displacement. Absolutely no difference in poser /ds/bryce/carrara.  I've made incredibly detailed displacements on a single poly. Its all about the textures there.

also something to remember .. in poser every morph adds the file weight of the origial obj again. So if the figure is 1 meg, a figure with 3 full body morphs is 4 megs.  For this reason alone a lower polycount version might be a good idea

Lyrra