A nit: did you go from Opus 4.5 to Fable? One of the big questions in my mind is how much of a real change Fable is over the existing models. Opus 4.5 -> 4.8 was also a major capability increase.
I've been using 4.6, 4.7 and 4.8 since each was released. I agree 4.5 => 4.8 is a jump in capability, but from my perspective was nothing like the jump from Opus to Fable. I encourage you to read the transcripts and form your own opinions, though!