1. Deployment Approach: Google Cloud Build is a continuous integration and delivery platform that is focused on building artifacts and deploying them to Google Cloud services. It follows a linear approach where each step depends on the completion of the previous one. On the other hand, Spinnaker is a multi-cloud continuous delivery platform that supports various cloud providers. It follows a parallel approach where it can deploy multiple instances simultaneously, making it more suitable for complex deployment scenarios.

2. Pipeline Configuration: Google Cloud Build uses the configuration file called cloudbuild.yaml that defines the steps required for building and deploying the artifacts. It provides a declarative way to specify the actions to be executed. Whereas, Spinnaker offers a flexible and visual pipeline configuration where users can define stages, which are individual tasks or actions, and arrange them in a sequence to create a deployment pipeline.

3. Integration and Orchestration: Google Cloud Build is tightly integrated with other Google Cloud services, allowing seamless integration with services like Cloud Source Repositories and Kubernetes Engine. It also offers a RESTful API for programmatic access. Spinnaker, on the other hand, is designed to integrate with multiple cloud providers and can orchestrate complex deployment workflows spanning across different cloud platforms.

4. Rollback and Roll-forward: Google Cloud Build provides limited rollback capabilities by allowing users to revert to a previous successful build. However, it does not natively support complex roll-forward and roll-back strategies. In contrast, Spinnaker offers sophisticated rollback and roll-forward capabilities, allowing users to easily roll back to a previous stable version or roll forward to a new version in case of issues.

5. Deployment Strategies: Google Cloud Build primarily focuses on deploying containerized applications using Docker images and Kubernetes manifests. It is well-suited for container-based deployments and provides native integration with Google Kubernetes Engine. On the other hand, Spinnaker supports a wide range of deployment strategies, including blue-green deployments, canary deployments, and rolling deployments, making it more versatile for different deployment scenarios.

6. Community Support and Maturity: Google Cloud Build is a relatively newer service compared to Spinnaker, which has been in development and production use for several years. Spinnaker has a more mature and active community, offering extensive documentation, support forums, and plugins contributed by the community. Google Cloud Build is constantly evolving and gaining popularity but may have a more limited ecosystem compared to Spinnaker.

In Summary, Google Cloud Build is a focused CI/CD platform for Google Cloud services with a linear deployment approach, while Spinnaker is a multi-cloud CD platform with a parallel deployment approach, offering flexible pipeline configuration, extensive deployment strategies, and mature community support.