EnMasse includes a broker as part of its functionality (ActiveMQ Artemis in
this case) but it offers quite a lot more functionality beyond the broker
related to scalability and deployment. I don't think it's really valid to
compare EnMasse to an ActiveMQ broker directly.
As Justin said, it's not really a direct alternative to ActiveMQ, and in
fact ActiveMQ Artemis is one of the core components in EnMasse.
EnMasse adds some management components to deal with scaling brokers
up/down in an OpenShift/Kubernetes environment + a higher level
configuration model to configure messaging infrastructure in a
declarative fashion. It also integrates the broker with the Apache Qpid