Both are real technologies and both work. The marketing around graphene is louder than the difference, so here is the honest version from someone who applies both.
A traditional ceramic coating is a silica (SiO₂) based liquid that cures into a hard, glass-like layer bonded to your clear coat. A graphene coating is the same underlying chemistry with graphene oxide added into the formulation.
Graphene is not a force field. It will not stop rock chips, it will not prevent a shopping trolley, and a graphene coating applied over unprepared paint will perform worse than a good ceramic applied over properly corrected paint. Preparation matters far more than which of the two you choose.
Our honest position: for a garaged weekend car, a quality ceramic is plenty. For a daily driver living outdoors, a ute, or anything parked under trees or near industry, the extra durability of a 10H graphene system is worth the difference.