Arbitrum Orbit excels at opex predictability because it operates on a pay-as-you-go model for L1 data posting. You pay a known, variable cost per transaction batch to Ethereum, directly tied to gas prices. For example, an Orbit chain posting a 100KB batch during low congestion might cost ~0.05 ETH, while the same batch during a spike could cost 0.2 ETH. Your primary cost is transparent and tied to a single, measurable on-chain action.