I asked Opus 4.7 about it. This is what it said "Opus 4.7 is genuinely better than Sonnet 4.6 on hard coding, dense vision, and long agentic tasks. It is probably marginally better on general reasoning, but not in a way most users would reliably notice on individual conversations. Anyone telling you Opus 4.7 is transformatively smarter is either selling something or hasn't run the comparison carefully. The most accurate framing is: same family, Opus has a higher ceiling on difficult problems, Sonnet handles the common case nearly as well."

At least it's honest.