Comparison of the different approaches

Just a personal opinion having worked on all these examples.
(Feel free to comment, add your findings or just disagree)

Bash

Pros:

Gives you full control and feels more direct
No conversion from the docker-compose file to another format necessary (e.g. compared to Ansible)
Easy to extend and adapt

Cons:

Scripting work needed
Not necessarily platform agnostic (e.g. compared to the usage of Vagrant/Ansible)
Pretty similar implementation on local vs. a cloud-provider implementation (if there is a docker-machine provider available)

Conclusion:

Good to learn, but probably not more than that.

Vagrant

Pros:

Platform agnostic
Many providers, such as VirtualBox, AWS, Azure, DigitalOcean, etc.

Cons:

Provisioning machines works perfectly in Vagrant, but the tool is just not built for deploying the swarm at the same time.

Vagrant/Ansible

Pros:

Platform agnostic approach, both Vagrant and Ansible support Windows & MAC/OSX

Cons:

Conversion of the docker-compose file necessary