Well, which orchestrator is best will depend on many things including what features and use cases are most appropriate to your environment.
For example, Swarm makes it easy to get apps up and running quickly and has full support for Windows containers, whereas Kubernetes has more configuration options and resource types for things like stateful workloads (e.g. StatefulSets).
You can use both within the same cluster too.
Hence its your own liberty to choose one depending on your environment and requirements.