I tried both separately, I can't recall resemblances. After your remark, I am going to give it a try hand in hand. I do find similarities between UII and Pierre Cardin pour Homme in the mid and base notes, UII being richer, more complex and long lasting than PCpH.
IMHO, the only one smelling alike the original Opium is JHL. I got compliments on it while being asked if I were using it.