I too am using GLM-5.3-flash in Pi and I've yet to encounter a scenario it couldn't handle. And the pricing is just incredible, I've handed it a previously unseen codebase, asked it to analyse it and build a new feature, came back after it had done so and the API cost was a fraction of a cent. It's $0.5/1M output tokens on OpenRouter.

If I really need to, I can escalate a task to Opus at $25/1M, and the results are good, but not 5000% as good.