You need to seriously think about the significance of MBA or MSA in the context of your whole career, esp given the current economic crisis, which will make graduate students more difficult to land a job either in US or China. Such professional programs are not omnipotent, unable to solve someone's career development problems once for all, even if such problems narrowly concern money and status.
If you would like to focus you career development in corporate finance sector, a CPA certificate is helpful and an MBA degree will prepare you knowledge regarding management, both general and financial. You can dig more info in this forum and consult with more friends here.
More importantly, if you tend to assume some management position in the future, you need to cultivate and trim you character (if one could do so). I think you understand the importance of personal character/disposition, the art of doing things in daily work, which concerns less with intellectual ability and more with sense of self- control with respect to anxiety, fear, greed, aggression and revenge.
Finally, I think 4-5 yrs is OK for mainland candidate, due to maturity/experience and financial capacity. | 
