I haven't seriously used GLM/Qwen/etc for agentic work. I will say, that the GPT and Claude models from 6 months ago were very usable within their respective agentic harnesses (this matters a lot). But there is no way you could convince me to go back to GPT-5.0 from GPT-5.6 for a serious amount of agentic work.

I could probably accomplish most of the same tasks with GPT-5.0, but it would take a lot more involvement from me, more troubleshooting, and significantly more time.