Define the quality floor
Tokens per second are useful diagnostics, but the business needs a task completed to an acceptable standard. Establish the task distribution, verifiers, latency, recovery, and operating budgets before comparing an architecture or device.
Separate bounds from measurements
A capacity or roofline model explains resource constraints under stated assumptions. It does not certify that a workload fits or that two model families provide the same quality. Compare the modeled envelope with a frozen measured baseline on the actual task.
Make the tradeoff visible
Context policy, state representation, batching, precision, and placement may change cost and latency. Each change also needs a quality and recovery check. The final decision should record the assumptions, measured results, and the boundary within which the choice is appropriate.