I'm definitely an ENFP and not an ESFP for the sole reason that my intuition is my strongest trait of the four. But my most defining quality is not my ability to inspire others - on the contrary, nothing makes me happier than performing, being in the limelight, and being a happy friend towards others. That's so ESFP, but I know I can't be one because my S is non-existent. If you look at the types' analyses, I am very ESFP-like - I'm a happy, go-lucky person whose strongest aspect is the performing, look-at-me aspect. But I'm also the ditziest, head-in-the-clouds person alive.
Have you met any other ENFPs with a strong attention-seeking streak, the desire to perform with their life (such as being a movie star or a Broadway star) and extremely comfortable and happy in the spotlight? I know it's not so black-and-white, and that I could just be a spotlight-hogging ENFP, but I definitely seem to fit ESFP more than ENFP (except for the intuition-sensing part).