I think it's very interesting to read the usage policy for the different systems and what's allowed and what isn't and it gives you an idea of what the different companies are really concerned about. I think anthropic has more requirements related to disclosure etc and is more of a hassle in general.
https://openai.com/policies/usage-policies/ https://ai.google.dev/gemini-api/terms https://www.anthropic.com/legal/aup