As someone building an AI company right now, my quick Pro/Con for 4o vs Claude 3.5:

Claude: subjectively sounds more human to me, and really nails data questions that 4o is lackluster at

4o: far better assistant logic reasoning. I can trivially break Claude's assistant (system prompt) instructions within the user prompt, where 4o succeeds in all of these tests.

Pricing and output speed, for our purposes, are functionally identical. Exciting to have a competitor in the space already who stands to keep openai honest.