External renderer comparison and ease of use

For all the slowest and most realistic renderers that Blender supports, including Kerkythea, Luxrender, Yafaray, Indigo, and Maxwell, which one has the least setup options? In other words, the material parameters are few (whilst still covering most lighting phenomena - i.e. path tracing realism), and where the final setup is minimal or nonexistent.

Actually, if anyone could help score out of 10 in each of the 5 attributes below for each of the above five renderers (10/10 is always better than 0/10), I would be very grateful. Even rough guess work would be great:

  • Speed (more = better)

  • Realism and the amount of light phenomena reproduced (more = better)

  • Number of parameters for materials (more = worse, apart from any that are absolutely essential to obtaining all / most light phenomena and material types)

  • Number of parameters for final render (more = worse, apart from no-brainer options like ticking off / on direct illumination, wireframe mode, or the max number of light reflections etc.)

  • Cost (more = worse)

My bias goes towards the last four, rather than speed. I want something that reproduces all or most lighting phenomena, but which is extremely easy to setup. Speed is no issue at all.

Finally, can any of the renderers (and even Blender itself) handle isosurfaces?