Brian and GD.....thanks.
i do have other chairs....but for me comfort is king.
this particular chair does have a high back; but the high back is narrow and not 'cupped' like many high back chairs.....all the surfaces roll away from my ears so don't really reflect, and the headrest keeps my head away from the back. i have compared it to my chair without a high back and the difference is quite marginal (more different than better or worse). my room is large enough that any rear wall reflections are very diffuse and not significant.
furthermore.....it is, by far, the most comfortable chair i have ever encountered. it is the 'zero gravity' chair since it removes the weight of your body from your spine and distributes it over your entire body.....i can (and do) sit in that chair for 10 to 12 straight hours.
life is balance.....and i have balanced comfort and performance.