Scale is important. Neo4j can help you achieve it in practice.
Chief Scientist Dr. Jim Webber talks about how 3 Neo4j machines can do the work of many times more machines running other NoSQL databases.
Learn more about how Adobe moved one of their key applications from MongoDB to Cassandra and then to Neo4j. With Neo4j, they achieved orders of magnitude faster response times, better functionality, and hosting new features with significantly less ops effort.