As a qigong exercise, Ma Litang's Tai Chi is good enough.

But if you aim at Tai Ji Chuan, you don't have to learn from him.

Tai Ji Chuan's famous Li Yaxuan's theory and boxing, Niu Chunming's "Evergreen Tree", Tai Ji Chuan and Dong Yingjie's Tai Ji Chuan videos are all representative works of Tai Ji Chuan.