Seems to me like they're somewhat trying to simplify now.
GPT-N.m -> Non-reasoning
oN -> Reasoning
oN+1-mini -> Reasoning but speedy; cut-down version of an upcoming oN model (unclear if true or marketing)
It would be nice if they actually stick to this pattern.
I suspect that "ChatGPT-4o" is the most confusing part. Absolutely baffling to go with that and then later "oN", but surely they will avoid any "No" models moving forward
But we have both 4o and 4.1 for non-reasoning. And it's still not clear to me which is better (the comparison on their page was from an older version of 4o).
Are the oN models built on top of GPT-N.m models? It would be nice to know the lineage there.