We've used Blazegraph at work for a project, and we have used a number of other graph databases.

Blazegraph is a very niche product and requires a lot of time for setting it up and adjusting it for your workload.

If Blazegraph peaks your interest then you should also look into Yarc platform by Cray.

Should you want to look more into graphs, but don't want to spend endless nights just trying to load your data then I would recommend Stardog, which has just been a pleasure to work with.