It depends on which program you are comparing with.

Generally speaking, RUC master program(professioanl) is among the tops of China. Of course, this one is not as good as the ones of Peking University, Tsinghua University, Fudan University and Shanghai Jiaotong University. However, it's better than others. (That's just from my personal perspective. No offend. )

When we are talking about professional master programs, we mainly focus on the placement of the students in this program. You can find out the data from RUC or other resource. Renmin University is a big name in finance industry. The professors there have connections with the industry. You can count on that and work hard in that way. 

As for the mentorship, there is no clear appointment of professor and student, as far as I know. Maybe it has changed. There will be several professors assigned as a group acting as mentors together. Things become tricky here, because this kind of loose bondage is an advantage for those who are active and smart. ("Smart" here is more of emotional intelligence.) If your performance is better than your peer, congratulations, opportunities for you will be much more. 

All the above is merely the babble from an alumni of RUC. May your study and life prosper in the future! Congratulations first.