Stephan Chow and Tony Leung are two popular HK actors during the similar period. While Tony Leung is famous for his charm and perfect annotation of the character's personality, Stephan Chow is well-known for his unique expression of humor. There is no better or worse between them. However, one thing sure is that one can't play the other's role well. I can't imagine Stephan played the role in the "Lust Caution". Maybe he can but it is not a suitable role for him.
Personally I like Stephan Chow a lot. His craze for acting and directing and his creativity and personality greatly attract me. I like his exaggeration and his cheesy jokes. You may not like it but it definitely leaves you deeper impression than many serious movies. When people criticize Andy Lau for his similar personality in each movie, the same group applauded at the vivid but similar personality of Stephan Chow in each of his movie. They believe it is a fashion.