Are you mainly using LLMs as a search replacement or augmentation? Are you using it in other capacities like code generation, etc?
I will share one surprisingly poor experience I had: I asked an earlier iteration of ChatGPT to build a probability model based on the FIFA tournament pools / brackets and current bookkeepers' odds. It made a complete mess of things, not demonstrating any understanding of how qualifiers would be paired up. It offered some case analysis where the cases were poorly defined and overlapping. Plus it got stuck in that obnoxious emoji-heavy Markdown table mode you see in all those GitHub READMEs (which otherwise hasn't been an issue for me). I thought it would be good at this, being a synthesis of basic mathematical analysis (probably following standard techniques) and basic research, but no.