Research/benchmarks aside, try giving a somewhat hard programming task to Opus 4 with reasoning off vs. on. Similarly, try the same with o3 vs. o3-pro (o3-pro reasons for much longer).
I'm not going to dig through my history for specific examples, but I do these kinds of comparisons occasionally when coding, and it's not unusual to have e.g. a bug that o3 can't figure out, but o3-pro can. I think this is widely accepted by engineers using LLMs to help them code; it's not controversial.
Research/benchmarks aside, try giving a somewhat hard programming task to Opus 4 with reasoning off vs. on. Similarly, try the same with o3 vs. o3-pro (o3-pro reasons for much longer).
I'm not going to dig through my history for specific examples, but I do these kinds of comparisons occasionally when coding, and it's not unusual to have e.g. a bug that o3 can't figure out, but o3-pro can. I think this is widely accepted by engineers using LLMs to help them code; it's not controversial.