A good improvement overall.

GPT-6 Luna now is 50% cheaper, which makes it have one of the best intelligence per cost ratios.

GPT-6 Sol is smarter, but seems to reason 2x more than GPT-5.6, which makes it 2x slow3r and 25% more expensive in practice.

[0]: https://aibenchy.com/compare/openai-gpt-6-sol-high/openai-gp...