- ZITADEL: If you want turnkey solution built for the cloud with a great support for B2B, a strong audit trail and self-hosting, but also the option for SaaS - Ory: If you want flexibility to customize all the stuff but are aware that it is not as turnkey as ZITADEL and Keycloak - Keycloak: If you want turnkey with a high maturity and a lot of features but some lack in regard to B2B, cloud native and support
This more or less reflects my opinion about Ory. I like the way they built their suite because its totally flexible. But it dislike the fact that it does not feel like a turnkey solution and needs some more work than plugin in a OIDC client.
So what we think and aim for is that ZITADEL combines the best of Auth0 and Keycloak [1] while bringing some unique features to the table. For example an unlimited audit trail (built with event sourcing), great self-service capabilities for B2B and B2C cases (customers can manage their own org, user, federation, access) and the possibility to soon run "serverless" (well at least as serverless container). With our cloud service we also allow customer soon to move their data around (see data location [2]). And all of this while being totally open source.
1. Funny image for this https://twitter.com/ffo_sesp/status/1519655412752162818?s=20...