Hi, this bassam (one of the maintainers on crossplane). We describe the relationship in our arch doc here https://docs.google.com/document/d/1whncqdUeU2cATGEJhHvzXWC9.... The following snippet is from that doc:

The AWS Service Operator is a recent project that implements a set of Kubernetes controllers that are able to provision managed services in AWS. It defines a set of CRDs for managed services like DynamoDB, and controllers that can provision them via AWS CloudFormation. It is similar to Crossplane in that it can provision managed services in AWS. Crossplane goes a lot further by offering workload portability across cloud multiple cloud providers, separation of concern, and a scheduler for workload and resources.