It'd be interesting to see how Sonnet 3.5 does at this. I've found Sonnet a step change better than Opus, and for a fraction of the cost. Opus for me is already far better than GPT-4. And same as the poster found, GPT-4o is plain worse at reasoning.
Edit: Better at chain of thought, long running agentic tasks, following rigid directions.
Edit: Better at chain of thought, long running agentic tasks, following rigid directions.