[zenlikethat]

They are different tools for different use cases.

Fig is a tool written in Python specifically designed to orchestrate groups of docker containers. It does not require virtualization by default, it talks directly to the Docker API (so you can use it directly on Linux without boot2docker/VirtualBox). It is useful because previously people were writing their own custom little Bash scripts etc. to bootstrap containers for e.g. a PHP app to run app code, a MySQL database, a redis instance and an instance of nginx to serve static files which are all meant to be tied together and work together in a specific way. One of the goals of docker is "one concern per container" so this helps people to use it in the right way and you don't have to, say, restart your database to restart your app (like you would if you crammed them all into one container).

Vagrant is a general purpose tool for automation and management of virtual machines written in Ruby. You specify configuration in Ruby. One of its goals is choice, so it has swappable "drivers" (so that you can use different hypervisors such as VirtualBox, Fusion, and HyperV) and "provisioners" (for installing software etc. when you bootstrap a new VM). I'm afraid I have to plead ignorance on the Docker provisioner, but mitchellh is the creator so I'm sure his input is sound.