Recs.
Updated
SpecsUpdate
Pros
Pro Simple and intuitive GitHub integration
CircleCI can be connected to any project that is hosted on GitHub by logging in using the GitHub OAuth and adding the desired repository.
Whenever a new commit is pushed to GitHub, CircleCI runs the tests that have been already defined and if none of them fails, the build is deployed to the runtime environment.
Pro Clean, intuitive UI
Circle CI's web UI is clean and easy to use.
It gives all the information for a single build in a feed and gives the explanation for each step of the build, what it's doing and what the step is related to. On the top it displays author information and the time and date when the build was started and finished.
This is all done by giving only the most essential information without clogging the screen.
Cons
Con Only supports GitHub
CircleCI has support only for projects hosted on GitHub so teams that use BitBucket or any other alternative to GitHub are forced to rely on another CI tool or use third-party solutions to be able to integrate CircleCI with BitBucket. One of those solutions may be Cloudpipes.