The calligraphy collections in Fan Ceng and Cao Cao are more valuable?

Cao Cao is a member of China Calligraphers Association and a pioneer of China calligraphy and painting. Not as valuable as Cao's calligraphy collection. Cao's calligraphy is worth collecting. Cao is a first-class calligraphy master of Chinese Painting and Calligraphy Academy, a cultural ambassador of China Painting Academy, and an academician of International Xizhi Painting and Calligraphy Academy.