On cursory first glance Sirius looks more advanced than Hazelcast: Sirius seems to provide substantially more flexible cluster topologies along with "real" consistency behavior (via Paxos). Plus, Sirius seems to come with a built-in persistence system with at least some thought applied to it, while last I checked Hazelcast left persistence entirely up to the library consumer.
As a disclaimer I haven't looked at the implementations of either, only the documentation (and I used Hazelcast in a project a while ago).
As a disclaimer I haven't looked at the implementations of either, only the documentation (and I used Hazelcast in a project a while ago).