I've been experimenting with both since the moment each came out. 4 games, 3 websites and 2 content creation engines later - I think I'm ready to share a bit of my experience and opinion.

WHAT I'VE NOTICED ABOUT FABLE

1. Gold in, gold out - meaning I've had the best results by making all my design decisions before giving Fable the kickoff information and prompt. It's much more comfortable making decisions by itself - decisions it won't tell you about - unless you explicitly tell it what it can and can't decide for itself up front.

2. It's a black box - which is an extention of the point above in a way. I've used the analogy of an agency when I've described it to people, i.e. it'll take a brief (what Fable itself describes as "an order") and go off and run with it, only coming back once it's done. I once had a Fable conversation work independently for 9 hours buidling out a client self-service portal for me. All I had to do was type 'Continue' once it hit its session limits every 5 hours.

3. It's insanely powerful - so if you've got everything worked out up front by thinking and working through it with an Opus conversation, you can get the most staggering results. It creates its own sub-agents, does its own testing and self-verification, and ships you back a finished product. It blew my mind.

BUT I PREFER OPUS 5

Why? Because it's not a black box.

1. It reports back - it seems to pause at natural phase gates and give an update on what it produced and why. There's a rhythm to it that keeps you the user involved.

2. It's just as capable of spinning up sub-agents and doing its own testing and verification.

3. It genuinely is a lot cheaper - for example when Fable runs on a task my Claude Max limits burn out in roughly 30 to 45 minutes (Fable is FAST). But then that leaves me twiddling my thumbs. Opus 5 feels more methodical somehow (which might just be because it comes back to the user, resulting in a slower cadence). Or maybe the better way of putting it is that Opus keeps you the developer involved throughout. And it feels like it's more interested in giving you exactly what you want. Fable doesn't do that - it basically just takes the brief and does its own thing.

I simply wanted to share my experience as I've quickly reached the point of familiarity and thought that might be valuable to others who are experimenting with these frontier models.

Look forward to your thoughts. Cheers.