The benchmarks everyone cites (MMLU, HellaSwag, etc.) measure knowledge or reasoning on curated datasets. For generating marketing copy, support responses, or blog posts, those scores don't translate.
In a SaaS context, you need to measure:
* **Business alignment:** Does it adhere to brand voice guidelines? Does it include required CTAs?
* **Consistency:** Output stability across 100 runs with the same prompt.
* **Operational cost:** Latency and tokens-per-second at your required throughput.
* **Drift detection:** When the model starts producing slightly more formal/informal tone over time.
If your eval doesn't include these, you're not measuring what matters for production. Start with a custom rubric based on your actual use case, not an academic leaderboard.
Prove it with a benchmark.