OrientDB is more similar to Neo4j, http://www.orientechnologies.com/orientdb-vs-neo4j/ and some folks think of it as a decent alternative to it https://medium.com/@KevinHoffman/first-exposure-to-orientdb-...

I didn't have any performance issues with OrientDB, but it's worth noting that I worked with relatively small datasets (e.g. graphs with ~1000 edges).

Titan, given that it runs on HBase or Cassandra, is on a whole different level compared to these two graph DBs. If you're working on a small app which needs an ebedded graph DB, you'll definitely not use Titan.