I don't know what is a CTX chip, I just try it on my Duo with Hsync and Vsync on my Projector, normally with its size, it should fit a PC engine too, so, to answer your question I didn't try it on another console than mine and I'm not interested to use S-video or composite as they are (normally) in lower quality.
I don't think this mod offer extra benefits, because I didn't have the possibility to see another kind of boards, just my previous composite, But I'm happy with the results. The extra test I have to try is to check if it works also on some VGA screens, that would be nice (for example I have a friend who don't care about TV and don't have one, but would appeciate to use its console on his computer screen).