Yao's workmanship isn't comparable to Chan's in my limited experience. Chan's is arguably superior. Yao is also relatively inflexible in terms of style; that is, he has his notion of what looks good and will try to persuade you to agree. That said, I think the "house style" is generally attractive, but if choosing Yao, you should make sure ahead of time that your general tastes align with his.
I would disagree on both counts. Having had suits from both in the past I have settled on Yao with considerable satisfaction and pleasure.