@lakewut
Rabbanut it kosher. They don’t keep the same chumras as OU (e.g. glatt). And OU doesn’t keep the chumras of the Rabbanut (e.g. chadash, chalav akum when it’s not powdered).
These are apples and oranges. The OU is also more centralized and standards are enforced uniformly. The Rabbanut is more decentralized more like a local vaad hakashrus, where each area goes by the rabbanim of their area, with national minimum standards and local enforcement.