Bantha is right (and Opera touched on this as well) we each need to do what is right for us and for the project we are doing.

And, the Real Skin Shader actually comes out nicely, even using the P4 Render engine (but, the displacement maps are ignored, mind you, this is a minor detail).  Back when I was only using P5 I would use the P4 engine for a number of renders if there was no need for raytracing or displacements.  Of course, I wasn't going for super-realism, either.

AO will not work without Raytracing, but if you are doing portraits, you might not always want AO shadows, anyway.

Here is a great lighting Tutorial by Bagginsbill for those who want to skip using AO.

http://market.renderosity.com/mod/forumpro/showthread.php?thread_id=2577132

Opera, that pic turned out really nice.  I didn't find the shadows on the daffodils destracting, but I don't know how to get around them.