We went to the branch located at south of Temple of Earth Park - take subway to Yonghegong stt (line 2), just across the stt. Ate here 2 twice ( need not make reservations; just walk-in ), due to the convenient location and long operating hours.
There is a lot of variety - with some items priced @ 8.80 yuan before 5 pm. Menu - in English/Chinese with colour pictures of each item. Service staff is helpful.
Found the food reasonable, for the price paid ( though I had eaten better dim sum in Spore ).