If you've been using each new step is very noticeable and so have the mindshare. Around Sonnet 3.7 Claude Code-style coding became usable, and very quickly gained a lot of marketshare. Opus 4 could tackle significant more complexity. Opus 4.6 has been another noticable step up for me, suddenly I can let CC run significantly more independently, allowing multiple parallel agents where previously too much babysitting was required for that.

In terms of real work, it was the 4 series models. That raised the floor of Sonnet high enough to be "reliable" for common tasks and Opus 4 was capable of handling some hard problems. It still had a big reward hacking/deception problem that Codex models don't display so much, but with Opus 4.5+ it's fairly reliable.

Honestly, 4.5 Opus was the game changer. From Sonnet 4.5 to that was a massive difference.

But I'm on Codex GPT 5.3 this month, and it's also quite amazing.

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