GPT-5.5 vs Claude Opus 4.7: 10 Real-World Tests — Which AI Wins?

Key Takeaways

• Setup: GPT-5.5 with extended thinking (paid plan) vs Claude Opus 4.7 with adaptive thinking on (paid plan with desktop app) — best-of-best comparison for each platform.
• Tasks covered: app building, writing, landing page design, business strategy, data analysis, teaching, video planning, and more across 10 rounds.
• Google Gemini scores both independently 1–10 per prompt, adding a third-party perspective rather than the creator's subjective judgment.
• Notable style difference: Claude Opus tends to produce consistent, same-style designs (same font, same layout) unless explicitly directed otherwise. ChatGPT GPT-5.5 tends to produce more varied, colorful output.
• Both platforms have dedicated coding environments — Claude Code (desktop app required) and ChatGPT Codex — but this test uses the base chat interface only for direct comparison.
• For the coding-assistant comparison specifically, see the Codex setup guide and the Claude Code setup guide.