We recently had a dialog with RedHat and touched on this topic. Here is what I take away from our conversation:

JBoss A-MQ is the messaging product JBoss will recommend for standalone dedicated messaging queue deployment.

HornetQ is ideally used within the JBoss AS for tight integration with the EJBs.

JBoss AS chose HornetQ as the MQ service implementation because it satisfies all the specs / needs of the AS at that time. It will continue be supported at least to the end of the AS support lifecycle.

I don't think they are dumping HornetQ, but I feel in many situations, A-MQ will be the one recommended in stead of HornetQ. It seems to me they are label HornetQ as "best used with JBoss AS".

Of course, a formal clarification from JBoss would be nice and should be what you rely your decisions on.

HornetQ is the JMS implementation within EAP 6. A-MQ is essentially an alternative for MRG-M, building upon ActiveMQ and Proton from the QPid community. Going forward it is our intention to look at how we can ensure that A-MQ, HornetQ, QPid and Apollo can be combined into a coherent messaging strategy. This will take some time and we'll be working it through in the relevant up stream communities. It's very early days on our own thinking yet, but I hope that Clebert and team will soon be at a point to discuss options etc. But HornetQ is definitely not going away any time soon!