K2.6 is cheaper than GLM5.2 (at least on DeepInfra) and I've found it works as good as Sonnet for my purposes. Both tend to think themselves into circles a bit and aren't super token efficient, but I've found GLM5.2 much worse on this count making K2.6 even cheaper than the per token price would make seem.

I find them to be about comparable, but I use them both for coding tasks and I'm happy with each. I like K3