OK within its limits
It's actually pretty reasonable to use if you just look at it from the user side as a way of running and managing your containers.
Get too far into trying to actually manage Kubernetes itself and messing with deploying the platform and it's a world of pain. Much easier to just pay someone to provide it than to DIY.
Biggest problem with most of these projects - Docker, K8S, OpenStack, Puppet - is that people writing & managing them get distracted by the shiny so you end up with some fancy features but lots of its barely alpha grade and deployment, management and maintenance are an afterthought if that. From that POV you could put them on the level of student project toys.