Zookeeper has a feature I particularly like that etcd does not (for now at least): it's possible to write to a node from a client such that the node will disapp

Zookeeper has a feature I particularly like that etcd does not (for now at least): it's possible to write to a node from a client such that the node will disappear if the client disconnects. This plus watching makes for a great liveness check between different machines.