Opus is at the same level as open weights models now. Okay, maybe a tiny bit better. So basically "nothing" - I don't see the point of using closed weights if there is an equivalent open weights model.
Opus is still significantly better than open weight models.
GLM 5.2 comes close on agentic tasks, but doesn't code as well.
Kimi 2.6 and Deepseek v4 Pro write great code but lose track when doing agentic workflows. They were better than Sonnet 4.6 but not as good as Opus. I haven't compared them to Sonnet 5 yet.
I use GLM 5.2 routinely for coding and agentic tasks. It is not without its quirks, but generally I find it on the level of Opus 4.7 or so. But without all these "cybersecurity" rejections.
GLM 5.2 comes close on agentic tasks, but doesn't code as well.
Kimi 2.6 and Deepseek v4 Pro write great code but lose track when doing agentic workflows. They were better than Sonnet 4.6 but not as good as Opus. I haven't compared them to Sonnet 5 yet.