The original piece I printed for this design was on cotton. I did some 'after Spoonflower' manipulation, but not an extensive amount. The below samples were printed on Poly Crepe de Chine and Silk Crepe de Chine. The design was created in Photoshop from my original photographs.
As you can see, there are two very different results and neither of them wrong, just different. The poly fabric is very true to color on the original design. The silk would have to have the saturation pumped up if I wanted the same results. The original cotton printed piece is closer in color to the silk. The poly is smooth, so the edges of the design are crisp. The silk has a sandy texture so the edges are softer. If you wanted a softer, more watercolor effect, the silk would definitely give you that result.
I found a piece of the cotton to show the comparison. The silk and cotton are similar in both color and edge quality of the design. Both are less saturated and have more of a watercolor effect. The polyester is sharper in edge quality and brighter in color.