I don't know if there is a lot of difference there, the most important thing, is, the surface preparation.
While I have used exhaust coatings, I usually just use POR manifold paint with, again good surface preparation.
I don’t think that Cerakote is done on the inside and outside of the piece, while other ceramic coat exhaust specialists (Jet Hot) coat both sides. This prevents mild steel from rusting from the inside out.