BB - I agree that SSS could be of value in some instances, but I found I was getting better results without it.  Attached image was just Alyson2, skin material with a single color map in Diffuse_Color, Reflect node (White, Qual 1, Soft 2.5), and a Cellular bump. 

Lights were 2 planes (one left, one right) at ambient value 6.  Pure white.

Render settings 40 IC and 50 ILQ, no shadows, no SSS.  I think the skin is a little oily.  I tried an edge_blend on the reflection softness and it worked a treat.

Pls excuse the color map silliness on her right hip and under her right arm (I got a bit excited in ZBrush adjusting the map).

I re-ran this render without any walls, and the result was very very similar.  The amount of light coming from the back wall back onto the figure is minimal.  Since the two planes are very bright, the reflect amount has to be dialed back (think it's 0.02 or in that region).  That's what killing the reflect from the back wall.  This could be solved by reducing the diffuse value of the lights from 1 down to something like 0.2 - then increasing the reflection amount.  Although one of the advantages of very more reflection values is that the skin does not reflect too much on itself.

I also ported this scene to both Lux and Octane.  The results were fractionally better (as you would expect), however rendertime was way more than Poser (I think even Octane was around the 4hrs mark, although that was with SSS on).

Creator of PoserPhysics
Creator of OctaneRender for Poser
Blog
Facebook