Verdict
Built from the measurements below
- Accuracy is too close to call: GPT-5.3-Codex scored 82.5% and Muse Wonder 78.8% on the same 80 questions, a gap within what chance alone could produce.
- GPT-5.3-Codex is 2.1× cheaper per question as billed ($0.01 vs $0.021), reasoning tokens included.
- Muse Wonder generates text 1.8× faster: 175 tokens per second against 95.
- GPT-5.3-Codex starts answering sooner: 1.4 s to the first token, against 16.1 s for Muse Wonder.
- Muse Wonder accepts more context: 1M tokens against 400k.
Which should you choose?
Choose GPT-5.3-Codex for the lower cost per correct answer ($0.013 against $0.027) and a quicker first token. Choose Muse Wonder for faster streaming and a 1M-token context window. The widest subject gap is in medicine: GPT-5.3-Codex answered 7 of 11 correctly, Muse Wonder 5 of 11. With so few questions per subject, treat this as a lead to test on your own prompts, not a result.
Accuracy gap +3.7 points (z = 0.60). We call a winner only when z is at least 1.96, the usual 95% threshold. Speed, latency and price need a 10% margin.