If I recall correctly... Yang Rui acted as Lu Wu Shuang in ZJZ's Shen Diao Xia Lu, as well as Zhong Ling in Tian Long Ba Bu.
I felt that the chemistry between Nicholas and Gillian was fine. They certainly looked good together! Having said that, I really don't think that they are the main couple - so the quality of their on-screen interaction didn't quite matter to me. Despite the fact that Nicholas and Gillian feature very prominently on the cover of my DVD boxset, it seems to me that Ben Yue and Bao Yu are the real stars of the show... While Da Zhang's fanatical search for swords drives the plot, the story is largely Bao Yu's adventure, and his growth from playful and ignorant boy to mature swordsman.
(And yes, the middle episodes were so draggy!)