In my Organization there is discussion going on OPA vs Zanzibar, After looking at SpiceDB, I am very much convinced with SpiceDB. Only valuable argument I see in OPA is its reduced network latency due to running as side service. Checking permission against remote service might cause delay if there is network latency (not because of SpiceDB, I tested it and it is able to do permission check ~15-20 MS for most of cases for me) but checking against local may cause consistency issue. Can you refer me some document where detail comparison is being done?