On top of that, I have to say that docker-compose even further increases the benefit of docker over vagrant, because it makes it very easy to share a whole environment that depends on other services (e.g. mysql, LDAP or whatever).
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There is definitely a benefit for using Docker over Vagrant. Vagrant is a resource hog and takes a long time to deploy as it is near a full distro.
Docker is great for personal projects, small dev projects, and large scale projects.
I'm not sure what coding language you are using but I have a robust docker container repo for review here: github.com/htmlgraphic/Apache
In just a few commands you can have a duplicate setup with very small resource footprint when compared to Vagrant.
On top of that, I have to say that docker-compose even further increases the benefit of docker over vagrant, because it makes it very easy to share a whole environment that depends on other services (e.g. mysql, LDAP or whatever).