O.k. so what changed?

from Face Off's settings to the compromise settings I moved:
number of raytrace bounces from 2 to 1
min shading rate from .50 to 1.0
number of pixel samples from 3 to 2
did not change the max texture size
max bucket size from 128 to 256

Comparing images it's hard to see much of a difference.  The one notable exception is in the area of the eyelashes - you'll notice the render at the compromise settings has eyelashes that are clumpier or less smooth, along with the shadows for the eyelashes.  There's also possibly a bit less smoothness in the shadow edges, and perhaps a bit less detail in the lips. 

For that price, I cut my render time in half, from 10 minutes to 5 minutes.

Some lessons learned going off the base line, here are the effects of changing individual parameters:

Moving the number of pixel samples from 3 to 2 took 1 minute off the render time but it seemed the resulting image was a  bit less clear
Moving the number of pixel samples from 3 to 1 took 3 minutes off the render time but gave unacceptable aliased jagged results

Moving the number of raytrace bounces from 2 to 1 took 1 minute off the render time with no noticeable results - however there's not much reflection or refraction going on here (some in the eyes which I see no difference in), so I don't know if this is the best test of that setting.

Moving the min shading rate from 0.50 to 1.00 took 4 minutes off the render time, with barely noticeable results except for the eyelashes and shadows of the eyelashes being a bit less smooth
Moving the min shading rate from 0.50 to 5.00 took 6 minutes off the render time, with noticeable results as the overall image became a bit more grainy, but the results weren't remarkably bad - they could be passable for quick decent quality results.

Moving the texture size from 4096 to 2048 took 2 minutes off the render time, giving slightly less texture detail resulting in a loss of sharpness, but provided decent quality
Moving the texture size from  4096 to 1024 took 3 minutes off  the render time, without much difference from the 2048 render
Moving the texture size from 4096 to 512 took 3 minutes off the render time, with noticeable results, definite loss of detail, especially in the lips - not worth it when it clocks in at about the same time as the 1024 size

Moving the bucket size from 128 to 256 took 3 minutes off the render - no change in image quality
Moving the bucket size from 128 to 512 took 3 minutes off the render - no change in image quality

So it appears the largest factor in the quality/time trade off is the shading rate.  When I left all the settings from Face Off the same and only moved the shading rate up to 1.0 and the bucket size up to 256 it took 4 minutes off the render (6 minute render time).  As bucket size does not affect image quality, it seems to leave the shading rate as the thing which will most greatly determines your render time vs. render quality.

As mentioned many times before you'd want to get your bucket size up as large as your system can handle as long as you can live with poser being somewhat less responsive while you render.

I think with my compromise settings or a very slight variation thereof I've found a good render setting which will produce quality results in less time.  I don't know if this helps anyone but me, but I'd love to hear feedback or have people contribute more information on this - especially if you're not seeing what I'm seeing.