Simon Willison’s Weblog

The issue with GPT-5 in a nutshell is that unless you pay for model switching & know to use GPT-5 Thinking or Pro, when you ask “GPT-5” you sometimes get the best available AI & sometimes get one of the worst AIs available and it might even switch within a single conversation.

— Ethan Mollick, highlighting that GPT-5 (high) ranks top on Artificial Analysis, GPT-5 (minimal) ranks lower than GPT-4.1