Stainless: The standout for maturity and idiomatic code generation. While method signatures across products may look the same, Stainless shines during developing & debugging - making their codebase easier to navigate. They have a practical separation of SDK configuration from OpenAPI specification, setting it apart from others reliant on OpenAPI overlays. The Stainless Studio also proved invaluable for refining our OpenAPI specs during our exploration phase.

Fern: Notable for being open-source, though not free. It provides a robust end-to-end Developer Experience, covering everything from SDKs and documentation to Postman collections. Fern uses an internal "Fern Definition" language (~ think Smithy), it's optional and enables capabilities like merging multiple specs, but is adding another layer to navigate in our view.

Speakeasy: Moves at a fast pace, which could be a double-edged sword. Rapid iterations may lead to frequent, potentially disruptive updates for customers. A minor gripe was the inclusion of "Speakeasy" in class names, which felt overly branded.

Liblab: Initially limited in language support, they've expanded but still lag behind in establishing a strong customer base, which might be a red flag for some adopters.

BTW all folks are very approachable and collaborative!