It probably depends on programming language and expectations.

This is mostly Python/TS for me... what Jonathan Blow would probably call not "real programming" but it pays the bills

They can both write fairly good idiomatic code but in my experience opus 4.5 is better at understanding overall project structure etc. without prompting. It just does things correctly first time more often than codex. I still don't trust it obviously but out of all LLMs it's the closest to actually starting to earn my trust