GPT-6 Astra or Opus 5.5 for Motion Design?

The author ran the same two jobs through Opus 5.5 in Claude Code and GPT-6 Astra in Codex, once each: the viral one-line showreel prompt and a 15-second launch teaser with real screenshots, logo and music. Astra was faster and looked more finished; Opus was more careful with music timing but skipped sound on the showreel. Ends with which model fits which workflow.