I didn't see any mention of quality in GP's post... For me Docker swarm is a simpler implementation than Kubernetes and likely more suitable for simpler deployments.
Kubernetes whilst a cool product still has a lot of rough edges even now. One I encountered recently was that to upgrade a locally deployed cluster from 1.4 to 1.5 the answer appears to be "re-install from scratch" as the upgrade script is still "experimental" (https://kubernetes.io/docs/admin/cluster-management/#upgradi...)
Kubernetes whilst a cool product still has a lot of rough edges even now. One I encountered recently was that to upgrade a locally deployed cluster from 1.4 to 1.5 the answer appears to be "re-install from scratch" as the upgrade script is still "experimental" (https://kubernetes.io/docs/admin/cluster-management/#upgradi...)