If you had this done or did it for your SO, who did you go through? Did it make a real difference in the job search to certify foreign credentials?

Are you talking about education certification ? I used IERF to evaluate my degree but I did it only because my current employer asked me to. Before that, I went from one temp agency to another and neither one of them wanted to look at my degree.

I think it highly depends on what kind of job that you are looking for, it might help for some jobs and it might not make any difference for other.