For code generation, nothing so far beats Opus. More likely than not it generated working code and fixed bugs that Gemini 2.5 pro couldn't solve or even Gemini Code Assist. Gemini Code Assist is better than 2.5 pro, but has way more limits per prompt and often truncates output.
I found Anthropic’s models untrustworthy with SQL (e.g. confused AND and OR operator precedence - or simply forgot to add parens, multiple times), Gemini 2.5 pro has no such issues and identified Claude’s mistakes correctly.
Don’t sleep on Codex-CLI + gpt-5. While the Codex-CLI scaffolding is far behind CC, the gpt-5 code seems solid from what I’ve seen (you can adjust thinking level using /model).