[kjnilsson]

No they do not replicate like classic mirrored queues do. They are much more similar to quorum queues in that they only (asynchronously) replicate the delta after a disconnection. After all both streams and quorum queues use log replication. They are also both quorum systems in terms of availability.

W.r.t quorum queue features set we are working on Message TTLs. Priorities we'll have to see. We want to provide something there but it may not be a priority queue as provided by classic queues as this isn't the best way to do priority based messaging.