Connectors are a powerful tool in GraphQL Federation that allow you to bring existing REST APIs onto the graph without implementing, deploying, and managing Subgraphs. However, they come with challenges such as being prone to the N+1 Problem, requiring complex configuration for handling different response types and status codes, and testing issues. Additionally, connectors might lead to leaking the REST API semantics into the GraphQL API, and input validation and sanitization can become a challenge. If used carefully, connectors can be a powerful tool to extend a federated graph with existing REST APIs, but if starting from scratch, it might be better to implement Subgraphs instead.