This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
From my discussions with Marek @ Rabbit about it, it should support "moderate" load on a single Rabbit instance and benefit from clustering for scaling up. The performance hit as compared to pure STOMP should be negligible. Does that help?