Hi,
I don't know any thing about Yip Pui. I suspect Chow is sifu Chung K Chow. I don't know how good he is, but I suspect he is pretty good. His video seems like he does good stuff. His wing chun is from Leung Sheung lineage indirectly through his teacher, so you should be getting some good stuff. I understand he has been exploring with other fighting methods in relation to wing chun and calls it Integrated wing chun. I don't know how traditional his current teachings are. But it seems to me you could do much worse that to study with him. He is worth checking out and seeing if you like what he offers. I believe one of his students is a member of the list and perhaps could shed more light.
I've only just discovered my error, and I'm going to have to replay whole sections of my life through my mind to see what confusions I may have caused or fallen foul of.
--Douglas Adams