Our whole DevOps stack consists of the following tools:

GitHub (incl. GitHub Pages/Markdown for Documentation, GettingStarted and HowTo's) for collaborative review and code management tool
Respectively Git as revision control system
SourceTree as Git GUI
Visual Studio Code as IDE
CircleCI for continuous integration (automatize development process)
Prettier / TSLint / ESLint as code linter
SonarQube as quality gate
Docker as container management (incl. Docker Compose for multi-container application management)
VirtualBox for operating system simulation tests
Kubernetes as cluster management for docker containers
Heroku for deploying in test environments
nginx as web server (preferably used as facade server in production environment)
SSLMate (using OpenSSL) for certificate management
Amazon EC2 (incl. Amazon S3) for deploying in stage (production-like) and production environments
PostgreSQL as preferred database system
Redis as preferred in-memory database/store (great for caching)

The main reason we have chosen Kubernetes over Docker Swarm is related to the following artifacts:

Key features: Easy and flexible installation, Clear dashboard, Great scaling operations, Monitoring is an integral part, Great load balancing concepts, Monitors the condition and ensures compensation in the event of failure.
Applications: An application can be deployed using a combination of pods, deployments, and services (or micro-services).
Functionality: Kubernetes as a complex installation and setup process, but it not as limited as Docker Swarm.
Monitoring: It supports multiple versions of logging and monitoring when the services are deployed within the cluster (Elasticsearch/Kibana (ELK), Heapster/Grafana, Sysdig cloud integration).
Scalability: All-in-one framework for distributed systems.
Other Benefits: Kubernetes is backed by the Cloud Native Computing Foundation (CNCF), huge community among container orchestration tools, it is an open source and modular tool that works with any OS.