It'd be interesting to see how this compares with other graph systems. For example, Neo4j, JanusGraph?

Good question! I am from the team built GraphScope.

Neo4j and JanusGraph are graph databases where GraphScope is not.

For end users, using GraphScope feels like using a python library like networkx (https://networkx.org/), and you can do graph analytics, gremlin queries and GNN sampling etc in a single place. But unlike NetworkX which does not support parallelization, the actual processing of (big) graphs is handled in a distributed k8s cluster in parallel on GraphScope.