Ask HN: Have you ever tried finding a co-founder on the YC matching program?

Have you ever had to find a co-founder or new people to help you with/join your project or start-up? Also considering the fact that they don't really advise to start a project or star-up with your friends. For instance, your friend might be a good developer but you want to find one who's better. Things like that. Would you suggest the Y-combinator co-founder matching program? why might it be better than other ways? Any advice on choosing a co-founder?