Yes, it is the holy grail. Yes, the documentation is a bit spotty in some cases. We've been using kubernetes in GCE for about 1 year. We run both interactive services and batch jobs in 2 clusters: dev and production. The production cluster runs fully with declarative configs (we have a jenkins instance that performs the deployments of committed k8s configs). There are a couple of features that we are missing: (pod anti-affinity now in 1.6) and better support for storage. But in general kubernetes has the right concepts for running services, imho. We have 0 ops people.
Our clusters run on large VMs with 10s of PODs in the same VM. We can get high cpu/mem utilization; resilience to failures; logging; monitoring (via prometheus - GCE /stackdriver is awful). I don't think there is anything out there that comes close in terms of supporting the right abstractions and being ready to use in production.