Well...personally I LOVED GeMi's chemistry in LiaoZhai, but CP3 not so much. I think FengMi's chemistry in Gong is just as good as GeMi's in LiaoZhai (although the rest of the story is terrible)--however, GeMi definitely benefited from a fantastic storyline/script ("Xiao Qian" is such a classic story after all) whereas FengMi had to make the best of a bad one...so I'm giving the edge to FengMi! XD (But I admit I am biased.)
Actually I did venture into GeMi's forum a few times out of curiosity and because I like GeMi's friendship. However, some fans there are so delusional I start to wonder whether me and the FengMi fans are delusional too! >_< They can basically relate everything and anything to a "sign" that GeMi are secretly dating...omg...totally ignoring the signs that HG mgiht be dating XJN and YM is likely dating FSF. e.g. the LeTV event, even though it was full of FengMi adorableness, somehow they interpreted it as "YM is trying to distance herself from FSF and looks uncomfortable beside him."

Err...I know I am biased, but even so I just do not know what they are seeing! O_o Some of them are also quite rude about FSF so I avoid that forum now--I do feel bad for them though--guess it's not their fault they are forced to speculate so much since they have so little material to go on. And some of them are quite reasonable. Also...I have seen a small number of FengMi fans being quite rude about Hu Ge too so it goes both ways I guess. (A pity, since I like both actors and think they both had great collaborations with YM.)