I got their z.ai plan to test alongside my Claude subscription; it feels about on par with something between sonnet 4.0 and sonnet 4.5. It's definitely a few steps below current day Claude, but it's very capable.
dumbness usually comes from lack of information, humans are the same way - the difference between other llms is that if opus has information it has a ridiculously high accuracy on tasks.
z.ai (Zhipu AI) is a chinese run entity, so presumably China's National Intelligence Law put in place in 2018, which requires data exfiltration back to the government, would apply to the use of this. I wouldn't feel comfortable using any service that has that fundamental requirement.
Google, OpenAI, Anthropic and Y Combinator are US run entities, so presumably the CLOUD Act and FISA require data exfiltration back to the government when asked, on top of the all the "Room 641A"s where the NSA directly taps into the ISP interconnects, would apply to the use of them. I wouldn't feel comfortable using any service that has that fundamental requirement.
I wouldn't use any provider: z.ai, Claude, OpenAI, ... if I was concerned about the government obtaining my prompts. If you're doing something where this is a legitimate concern (as opposed to my open source stuff), you should get a local LLM or put a lot of effort into anonymizing yourself and your prompts.
