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.
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.
When you say "current day Claude" you need to distinguish between the models. Because Opus 4.5 is significantly ahead of Sonnet 4.5.