I worked with a guy who used it exclusively. It had a tendency to enhance highlights (on the nose and forehead) as well as create some odd hair colour highlights. This was especially evident as exposure increased. Most of it was subtle and nothing to cause the jobs to be bounced. NC on the other hand is smooth from light to dark is easy to balance colour and has a palette that really complements skin tones of all types.
I say this, but tend to never shoot traditional portraits. You can probably disregard anything I say when it comes to portraits and skin tone. I would rather have a 2 stop pull on an 800iso film and have no contrast and the grain the size of grapefruits or crossprocess e6 materials so that the facial features float in a puddle of pure white skin than shoot a person so they appear as they ‘should.’