I've been using GLM-5/5.1 for about 6 months and it has been a fairly capable model. I've seen a lot of mixed opinions that tend to align with harness usage so it is worth trying out a couple with a model before writing it off. For example, I'm using crush and have had a good experience while others using CC have had a much more mixed experience. For task complexity, I treat it as I would sonnet with the same care in building out plans/prompts before firing it off and letting it go.

I use intelliJ for much of my development and also set the built in AI tools to use my GLM sub (BYOK) and it has worked out well albeit a bit slow.

Overarll, it's my main model and has been getting better with each release.