For the particular task I'm working on (a mathematical task in validated numerics), even Sol has generally just repeatedly given up. I asked it for the main problems it could not solve, gave them to Fable, and Fable solves them, every time.

There is a clear hierarchy here and Fable is well and truly at the top for very tough tasks. It just sucks that Anthropic is so incompetent at delivering a cost-effective experience without the uncertainty of it getting pulled. It doesn't matter how strong their model is, customers will turn away.