Opus 4.8 xhigh is my daily driver for everything. I'd say Fable's edge is visible when designing for a complex problem with no obvious, idiomatic solutions. It is good at greenfield designs, and good at pointing out the pros and cons of hard design choices. I now do designs with Fable, and do implementations off those designs with Opus. Pretty happy. For a while I was using Fable for everything, but burned through a lot of real money for not much value, I think for coding its slow and not at all better than Opus.