We hate header wrap, so for those reading along we need to say all header makers we know find you have voided your warranty if you wrap it, because it traps moisture against the metal and causes rapid wasting away of the metal surface, welds, etc. You trap enough heat, you change the metal properties over time, welds fail, etc. Wrapping headers was a hotrod thing, and the hardcore guys doing it were rebuilding their headers every season anyway. Then it became a street 'cool' factor thing and street guys did it and their headers fell apart eventually, or the car burned to the ground after the wrap absorbed enough oil over time and eventually became a perfect wick.
But to answer the question, the best wrap beats the best ceramic on keeping heat within. We still think it is a bad idea. Note our Track Dog Header Heat blankets don't have the issues of wrap, because they don't fully wrap each tube, moisture can escape.