I just wanted to throw into the mix Rancher. Rancher is a more recent comer into the space and still in beta. Rancher focuses on simplicity, flexibility, and pragmatic solutions for Docker based infrastructure. Rancher is different in that it can be deployed in conjunction with all of these systems mentioned or can be ran as a replacement. It includes a scheduler, load balancing, health checks, service discovery, application templating based on compose syntax, storage management, application catalog, upgrade management, github/ldap integration, UI, API, CLI, etc.

Disclaimer: Co-founder of Rancher Labs and chief geeky guy behind Rancher