Weirdly enough, I agree with both sides. Opus beats every version of GPT 5 as a chat interface, hands down. ChatGPT, at this point, is mostly me correcting its output style, cadence, behavior, etc, and consistently remaining dissatisfied, meanwhile Opus one-shots things I didn’t even think it could (Typst code). All that said, I do my programming in OpenAI’s Codex app for Mac. It has completely dominated Claude Code for me. I’ll only ever use Opus to check 5.3-Codex’s work. Very weird world we’re living in. I hope it gets even weirder once Deepseek does whatever they’ve been cooking.