I tried to have at least one Peking duck meal per day in Beijing, because why not! 

Here are the ones I tried and in order of my preference which solely pertains to the Peking duck quality per se. 

Sheng Yong Xin (晟永兴) 
One Michelin starred restaurant at their Sanlitun outlet. Excellent service and food at this upscale restaurant, their Peking Duck is the best for me. With caviar no less. 
Address: Various locations 

Da Dong (大董) 
One of the more upscale spots for Peking Duck, their duck skin is crisp, and they have a unique crispy puff to have with the duck meat. Overall, prices are on the high side, but the Peking duck is relatively good. 
Address: Various locations 

Siji Minfu (四季民福) 
One of the most famous Peking Duck brands in the city. There are many outlets, but each outlet is still quite packed so plan well ahead. Dishes are very good value and while their Peking Duck has no fancy caviar, the portion is very generous, and quality is very decent. 
Address: Various locations 

Haitang (海堂) 
A Cantonese restaurant which is very modern and sleek. Their Peking duck’s presentation is the most unique of all we tried, presented in a three-tier antique lacquerware. The crisp skin is topped with 8-year-old Kaluga caviar and layered with goose liver, green apples and toast. Every dish I had other than the duck is consistently good. 
Address: Various locations 

Xin Rong Ji (新荣记) 
While I was not particularly at the three Michelin starred restaurant for Peking duck, I added it during our set dinner meal as the 28-day-old baby Peking duck is available exclusively at the Xinyuan South Road branch. The Peking duck skin is topped with caviar, and overall, it is a decent one if you still have space for it. Afterall, the brand is not a Peking duck specialty restaurant like some of the above. 
Address: China, 8, Chaoyang, Xinyuan South Road, 8号CN 北京市1层启皓北京东塔 邮政编码: 100027

Ranted by The Ranter