What I like about Vagrant is that while a provisioner can help, it's not mandatory. If you're stuck with a legacy "enterprise! It sings, it dances, it crashes if you look at it funny!" application with a lot of special requirements, you can get up and running pretty quickly with a little bash and perl. I whipped up a Vagrant script for our app which is capital-F Finicky.
If you're curious, here's the vagrantfile and bootstrap script: