My (admittedly one person's anecdotal) experience has been that when I ask Codex and Claude to make a plan/fix and then ask them both to review it, they both agree that Codex's version is better quality. This is on a 140K LOC codebase with an unreasonable amount of time spent on rules (lint, format, commit, etc), on specifying coding patterns, on documenting per workspace README.md, etc.