"Cheap" is up for debate, but the models themselves are great. Kimi K3 (and now 3.1 Pro) was the first open model I played with and didn't think to switch back to a frontier model. Now it's my daily driver and I have zero complaints.

The frontier labs are in a tough spot. It's hard to justify their cost when you can get something that's easily as good for cheaper (and anecdotally, more reliable/accessible). I do HITL so my perspective will be different than a fully-agentic setup, but as soon as I started using open stuff regularly, I realized that any moat the US labs had built is drying up.