I use both. I avoided codex in late 2025 because it was slow as molasses. I tried it again in February and it was on par with Opus speed.
I like codex(gpt-5.4 high) more for its ability to nitpick my PRs and find bugs. I like opus 4.6 much better for anything dealing with visuals, but I feel its rule adherence is inferior and it is not nearly as thorough on code reviews.
I like working and building better with claude, I like fixing bugs better with codex. Also, claude is much better and faster evolving with skills, plugins, new features I find useful, etc. Codex is always a month behind or more.
I did both for a month at higher tiers, $200 Claude Max and $200 ChatGPT Pro. I was always having to conserve my usage with claude, with codex I could just let it run wild with no cares. In the end, I downgraded claude to the $20 plan and use it on occasion, and I have kept the $200 codex sub.
I also have Claude at work, so I'll know pretty soon if I want to swap subs again, but for now, I'm sticking with codex at home.
> I tried it again in February and it was on par with Opus speed.
I'm not finding that, like not even close. I'm using it mostly to write specs and docs and having Claude and Gippity check each other's work and fix things. It's looking into other previously written MD docs, and checking against 3-4 multi-thousand file Ruby codebase(s).
5.4 takes about 50% longer, almost without fail. I'm using 'medium' effort on both.
Might be a difference in use cases. Mostly working in repos under 100k LOC, most of those are under 30k. Primarily golang, python, and terraform. Also a lot of interactive troubleshooting of Kubernetes, GHA, hardware debugging and application debugging.
I like codex(gpt-5.4 high) more for its ability to nitpick my PRs and find bugs. I like opus 4.6 much better for anything dealing with visuals, but I feel its rule adherence is inferior and it is not nearly as thorough on code reviews.
I like working and building better with claude, I like fixing bugs better with codex. Also, claude is much better and faster evolving with skills, plugins, new features I find useful, etc. Codex is always a month behind or more.
I did both for a month at higher tiers, $200 Claude Max and $200 ChatGPT Pro. I was always having to conserve my usage with claude, with codex I could just let it run wild with no cares. In the end, I downgraded claude to the $20 plan and use it on occasion, and I have kept the $200 codex sub.
I also have Claude at work, so I'll know pretty soon if I want to swap subs again, but for now, I'm sticking with codex at home.