Why should I use Drone vs Other Docker-based CI/CD platforms

I am using a pure Docker microservice site. At the moment I have started using Codeship to provide continuous integration and continuous deployment services. It was fairly straightforward, and free!

After looking around I've found that many big companies use Drone which is a CI/CD service that you host: drone.io . It looks really cool.

My question is, for medium sized projects such as mine, what is the difference between something like Drone and hosted CI/CD solutions?

PS. I use AWS and Azure for my container services.