Author here, it's the first time I hear about ElasticBox here, but it sounds interesting - I see that it supports docker too.

Before Docker we used Vagrant with virtual machines. It's a decent tool, but it doesn't really help with deployment - you don't ship virtual machines from vagrant, as you can with Docker containers and with Vagrant - developer's machines tend to diverge.

We've chosen Docker because it's lightweight, portable and we've seen lots of potential in this tool. It's ecosystem grows really fast, but docker is pretty stable now.