It's odd because I no longer really like ChatGPT. For chat-type requests, I prefer Claude, or if it's knowledge-intensive then Gemini 3 Pro (which is better for history, old novels, etc).
But GPT 5.3 Codex is great. Significantly better than Opus, in the TUI coding agent.
I don't know about Opus, but Codex suddenly got a lot better to the point that I prefer it over Sonnet 4.6. Claude takes ages and comes up with half baked solutions. Codex is so fast that I miss waiting. It also writes tests without prompting.
But GPT 5.3 Codex is great. Significantly better than Opus, in the TUI coding agent.