[bogomipz]

Etcd looks more promising?

Zookeeper has been around now for over 5 years with an extremely large install base.

Kafka, Hadoop, Solr, Mesos and Hbase projects that leverage Zookeeper distributed coordination.

Zookeeper has already delivered.

[harlowja]

I would tend to agree, knowing what zookeeper has been doing and actually using zookeeper (and etcd) I can say that the API and the primitives offered by zookeeper are IMHO better (although this multi-version concurrency control model is interesting) and more mature.

It feels like etcd is 'still discovering itself' for lack of better words.

Btw: https://issues.apache.org/jira/browse/ZOOKEEPER-2169 (this is the equivalent of TTLs for zookeeper).