Which doctor is better in orthodontics in Peking University Stomatological Hospital?

My girlfriend just had a correction, and I found that Beikou is a better doctor of Dawning in Invisalign. After seeing several doctors, it took me more than a month to decide.

I went to see this doctor twice. It's my first time to go to the hospital, but the doctor only visits on weekdays, so I went to the private clinic where Dr. Shu visits. It was a visit on Saturday, in Guangqumen, but closer to where we live.