Why would I choose KubeOne over Kubermatic Kubernetes Platform even if for now I would only want to run a single cluster? Maybe I want to run more clusters in the future.
TL;DR Start with KubeOne and use Kubermatic when you need more than one cluster.
There are multiple reasons to run either KubeOne or Kubermatic Kubernetes Platform. Most of it depends upon your exact architecture and requirements. At the most basic level, KubeOne is easier to implement and maintain. It requires less compute resources and has less moving parts for an operator to maintain. If you running Kubernetes in a resource constrained environment or only have a small infrastructure to manage, it makes more sense to run KubeOne. When you need to manage more clusters or ones of large size, it makes more sense to run Kubermatic Kubernetes Platform. There is also a migration path from KubeOne to Kubermatic Kubernetes Platform. Since Kubermatic Kubernetes Platform needs to run in a Kubernetes cluster, we usually run it in a KubeOne Cluster. Thus you can start your Kubernetes PoCs with KubeOne and when they are ready to grow, you already have a cluster to install Kubermatic Kubernetes Platform into while gaining familiarity with the Kubernetes Operator concepts baked into both pieces of software.