I Tested GPT-5.3 Codex vs Sonnet 4.6 vs Gemini 3.1 for Vibe Coding — Here’s who Winner | by Dan Cleary | CodeX | Feb, 2026 | Medium

That being said, Sonnet is the clear winner (still) even over more “powerful” models like Opus 4.6. GPT-5.3-Codex is interesting and I use it sometimes for deeper dives into a codebase, but not for much else.