I usually prefer old-school ID/password because of how generous Facebook and other services tend to be with personal information. It was a nightmare having LinkedIn scrape me from top to bottom of email contacts.
This talk does an excellent job of showing how site's like Facebook lie about access they offer to 3rd parties:
But if it's a social media network like Github, I'm usually ok with it, because I can control the access over the important aspects (like repos).