I have built several agents based on OpenAI now that are running real life business tasks. OpenAI's tool calling integration still beats everyone else (in fact it did from the very beginning), which is what actually matters in real world business applications. And even if some small group of people prefer Anthropic for very specific tasks, the numbers are simply unfathomable. Their business strategy has zero chance of working long-term.

In writing code, from what I've seen, Anthropic's models are still the most widely used. I would venture that over 50% of vibe coded apps, garbage though they are, are written by Claude Code. And they capture the most market in real coding shops as well, from what I've seen.

Just out of interest, why do you want to move? What's wrong with Claude and Anthropic in your view? (I use it, and it works really well.)