I find that o1 and Sonnet 3.5 are good and bad quite equally on different things. That's why I keep asking both the same coding questions.
Also, for me 50% 50% for Sonnet and o1, but although I'm not 100% sure about it, I think o1 is better with longer and more complicated (C++) code and debugging. At least from my brief testing. Also, OpenAI models seem to be more verbose - sometimes it's better - where I'd like additional explanation on chosen fields in a SQL schema, sometimes it's too much.
EDIT: Just asked both o1 and Sonnet 3.5 the same QML coding question, and Sonnet 3.5 succeeded, o1 failed.