1. Integration With Source Control: Bitbucket Pipelines is tightly integrated with Bitbucket Cloud, allowing seamless setup and configuration within the same platform. On the other hand, Shippable supports multiple source control providers including GitHub, GitLab, and Bitbucket, offering more flexibility in choosing the repository hosting service.

2. YAML Configuration: Bitbucket Pipelines uses a YAML file for configuration, providing a straightforward and simple way to define build pipelines. In contrast, Shippable uses both YAML and their own declarative configuration format (shippable.yml), offering users multiple options for defining their pipelines.

3. Pricing Model: Bitbucket Pipelines offers a pricing model based on build minutes, with a limited free tier and then charged based on usage. Shippable, on the other hand, offers a freemium model with limited functionality in the free tier and additional features available in paid plans, making it more suitable for larger organizations with specific requirements.

4. Environment Flexibility: Bitbucket Pipelines allows users to define custom Docker images for their build environments, providing more flexibility in configuring the environments as per project requirements. Shippable offers predefined environment images with the ability to customize them, which can be convenient for users who prefer starting with pre-configured environments.

5. Built-In CI/CD Tools: Bitbucket Pipelines comes with built-in CI/CD tools and functionalities, allowing users to easily set up continuous integration and deployment pipelines without the need for additional plugins or tools. In comparison, Shippable offers a more modular approach, where users can integrate various tools and services to create customized pipelines according to their specific needs.

6. Community and Support: Bitbucket Pipelines benefits from the large user base and community support of Bitbucket and Atlassian products, providing users with a wealth of resources and knowledge sharing. Shippable, while also having an active user community, may have fewer resources available compared to Bitbucket Pipelines, impacting the level of community support and documentation available.

In Summary, Bitbucket Pipelines and Shippable differ in their source control integration, configuration options, pricing models, environment flexibility, built-in tools, and community support, offering users various choices based on their specific requirements.