On my personal test bench, when compared to other inexpensive models, GLM 5.1 provides the answers that I would consider most complete or satisfying (these are subjects that I consider myself an expert in). The answers tend to be more comprehensive, nuanced, and include references that I would consider the correct ones (if given access to web search).
I also find it a joy to code with, somewhere between Sonnet 4.6 and Opus 4.6 (have not tested Opus 4.7 yet).
Finally, just gauging by pelicans, it kind of stick out: https://simonwillison.net/tags/pelican-riding-a-bicycle/
There is one important difference, which is that Claude and Codex will both refuse if I ask them to touch anything related to security. But so long as I’m just studying algorithms and things like that, they’re totally fine with it.
That said, Codex especially will sometimes randomly give me a cybersecurity warning and stop responding. It’s random but happens maybe 2-3 times per day if I’m doing heavy reverse engineering work. Claude is much less fussy unless, once again, you’re explicitly trying to touch anything related to licenses, passwords, etc.