Cedar is an open source policy language and evaluation engine 3 years ago
Evaluated this recently for my company.
Pros
1. Cedar is great and very expressive and fits many many use case.
Cons
1. The price. Was too expensive for our scale
2. As another commenter has pointed, Cedar/AVP expects you to send all the contextual data as part of the Authz request. It only persists the policy.
3. There is no concept of role based lookup. E.g I cannot query who has what access