Dynomite for production proven, limitless scale for Redis.
Provides ability to Redis for both in-memory and on-disk workloads.
Dynamo-inspired linearly scalable, shared nothing multi-master architecture. Pairs well with Cassandra.
Supports pluggable backends (ex. RocksDB).
Been in production 2+ years. One of the larger clusters handles over 3.6 million sustained ops/sec in production, every day.
The benefit of Dynomite's support for the Redis API + protocol is a.) you can use any Redis client and b.) the same code can be used for standalone Redis on your laptop and on a distributed Dynomite cluster.
Also you were a speaker at Data Layer right?
There are two answers to your first question.
1. Dynomite pairs well with Cassandra. At scale, Cassandra is not a speed deamon when it comes to reads. Dynomite helps to improve Cassandra's read performance.
2. The use case for Dynomite as the primary database is for workloads that require high throughput and low latency. In other words, Dynomite delivers consistently lower latency at any scale.