The answer really depends on what you mean by "multi-master" - particularly whether you're looking for synchronous or asynchronous solution, what consistency model you need (strongly consistent cluster or nodes consistent independently), and what are your goals (write scalability, read scalability, disaster recovery, ...).

BDR is meant to be asynchronous multi-master, i.e. a collection of nodes that are strongly consistent on their own, but the changes between the nodes are replicated asynchronously. Great for geographically distributed databases (users access their local node), for example.