Nice to see View Stamped Replication getting some love, to balance out all the Raft mania. Having such an essential core service implemented in a low-dependency non-GC runtime is good too.
The more recent "Viewstamped Replication Revisited" paper is probably my favorite introduction to consensus protocols and their use in a real system: http://pmg.csail.mit.edu/papers/vr-revisited.pdf