The main difference are the performance and a better support of commands (almost all of them are available right now). Rediscala matches redis type answer to scala types.

Redis serves 1 req at a time, but you can write to Redis socket and read from Redis socket during that time.

Rediscala (the RedisClient) use 2 actors: The first one handle I/O (I/O bounds). That actor also merge redis requests in a buffer, so there is less messages (but bigger) going to the TcpWorker (akka worker handling a tcp socket). The second decode replies (CPU bounds)