But according to their benchmarks Opus 5 outscores Fable 5 on basically everything. So which one is “better”?

Maybe more accurately I should have said “larger”. Fable has the most parameters, Haiku has the fewest.

Also fwiw I’ve never found LLM benchmarks to match reality based on my own usage, not for the large frontier models or smaller open weight models so who knows if Opus is actually better than Fable (I doubt it).

I think the problem is that Fable 5 is probably a bit outdated right now.

Fable 5.1 or whatever they go with will be the stronger version vs Opus 5.

From about 2 hours of Opus 5 use , I would say it is quite impressive.