True, Rama does have a learning curve. It's easier to explain why its indexing capabilities are so powerful, as data structures vs. data models is fairly relatable to most devs. But I actually consider its dataflow API to be the bigger breakthrough. Our Twitter-scale Mastodon implementation and examples in rama-demo-gallery are demonstrations of this.

Also, Rama has a first-class Clojure API (I should probably update the website).

https://github.com/redplanetlabs/twitter-scale-mastodon https://github.com/redplanetlabs/rama-demo-gallery