The most valuable features are: 

• MySQL drop-in solution: MemSQL supports the MySQL protocol, and many functions are similar, so the learning curve is very short. Developers were able to code against MemSQL the same day. They configured MemSQL in Docker and were up and running.
• MemSQL built-in pipeline: You can connect MemSQL directly to an S3 bucket and it will ingest its data automatically. There is no need to create a lambda function. It just works. You can connect to Kafka, HDS, and other protocols.
• Support for CTE, Window, Stored Procedures, functions (UDF, Table) are all included. MemSQL is a full-blown database solution. 
• Replication: A MemSQL cluster can replicate to another cluster. This is a great feature, allowing you to have one cluster that does all the heavy work, and a Replica for reads. 
• MemSQL supports high concurrency, and scaling horizontally is limitless.
• I really like the MemSQL portal (portal.memsql.com). Creating more labs is the best way to introduce people to MemSQL.