"Ansible is simple, which is a major strength", it "works by connecting to a server using SSH, copies the Python code over, executes it and then removes itself".
"Ansible Tower is the Enterprise version, it turns the command line Ansible into a service, with a web interface, scheduler and notification system."
"you can’t have long-running tasks."

"StackStorm is designed as a highly-configurable if-this-then-that service. it can react to events and then run a simple command or a complex workflow."
"MongoDB can be scaled using well-documented patterns." "StackStorm extensibility system is a key strength." "If StackStorm were a programming language, it would be strongly typed."

"Salt was born as a distributed remote execution system used to execute commands and query data on remote nodes."
"Ultra high-performance for large deployments." (LinkedIn use it)