The guys of those two companies made a real great job providing those two graph databases. Each of one has advantages: Cypher is a quite good query language for graph data in Neo and Orient manipulates multiple data models with schemas (which is quite important for GraphApps).
We say thanks for that.
Other graph databases are emerging (we are looking at ArrangoDB currently) but we don’t support them yet. Anyway, our Framework is so adaptative that any new driver for any new graph database is extremely easy and quick to create.
We also want to thank the people from Franz, the leader in semantic graph databases with their great database AllegroGraph. As occasional lispers and graph fanatics, AllegroGraph was a great source of inspiration for us.