Honestly I never heard of it, I had a few in mind but that wasn't one. I'll give it a try next time I need a graph db maybe it can scratch my itch so to speak.

My concerns basically range around memory consumption, query language and language ecosystem.

Edit: Oh and I guess around like functional extensibility. The last time I used a graph DB I had to export from the db itself to HDFS and use Spark to do things like PageRank and I'd rather be able to write that natively in their query lang or some like UDF equivalent.

That's what you can do in Neo pretty easily. The DS library offers a bunch (50+) algorithms to run on the graph data directly or projected, e.g. PR on 117M wikipedia links runs in 20s.

I've had bad experience with Neo4J's memory consumption so I'm wary of that to be honest. I don't disagree that it has those things but we actively chose to go against it because of past issues with resource usage.