My benchmark for this has been asking the model to write some tweets in the style of dril, a popular user who writes short funny tweets. Sometimes I include a few example tweets in the prompt too. Here's an example of results I got from Claude 3 Opus and GPT 4 for this last year: https://bsky.app/profile/macil.tech/post/3kpcvicmirs2v. My opinion is that Claude's results were mostly bangers while GPT's were all a bit groanworthy. I need to try this again with the latest models sometime.