Rice Flour in Shortbread: Yes or No?

First thing Saturday morning of the holiday weekend I baked shortbread.  This week was a simple comparison of two recipes:  one with 100% all purpose flour, one with 75% all purpose flour and 25% rice flour.  Everything else was the same- ingredients and process:

Pan:  8 inch cast iron skillet
Oven temperature:  300 degrees F
Baking time:  40 minutes
Process until creamy:  1/2 c. salted butter
                                    1/3 c. powdered sugar
Add:  1 c flour
        
Both results were quite good.  The batch with rice flour was the family taste test favorite.  The had a more even texture, and practically melted in your mouth.

We had dinner guests for the holiday, and there is no shortbread left to photograph!